TodoApp.MAUI: Replace obsolete Page.DisplayAlert with DisplayAlertAsync in AlertService (CS0618) #516

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Closed
TodoApp.MAUI: Replace obsolete Page.DisplayAlert with DisplayAlertAsync in AlertService (CS0618)#516
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ExamplesGood First IssueGood for newcomers

Description

@adrianhall
adrianhall
opened on Jul 7, 2026

Summary

Discovered while adding Windows CI coverage for TodoApp.MAUI in #510 (PR #514, build-samples-todoapp-windows.yml). Building the sample produces a CS0618 obsolete-API warning:

Services\AlertService.cs(14,12): warning CS0618: 'Page.DisplayAlert(string, string, string)' is obsolete: 'Use DisplayAlertAsync instead'

Root cause

samples/todoapp/TodoApp.MAUI/Services/AlertService.cs:14:

publicTaskShowErrorAlertAsync(stringtitle,stringmessage,stringcancel="OK")=>Application.Current!.Windows[0].Page!.DisplayAlert(title,message,cancel);

.NET MAUI has deprecated the Task-returning Page.DisplayAlert(string, string, string) overload in favor of Page.DisplayAlertAsync(string, string, string), as part of a broader naming-consistency pass adding an explicit Async suffix to async MAUI APIs. The compiler warning itself names the replacement.

Additional information needed

None — this is a like-for-like rename with an identical signature/return type (Task), so it should be a mechanical, low-risk change. Worth double-checking the DisplayAlertAsync overload signature against the installed Microsoft.Maui.Controls package version (10.0.40, per the .csproj) once picked up, in case the parameter list or overload set differs slightly from DisplayAlert.

Suggested fix

Replace the call with the non-obsolete equivalent:

publicTaskShowErrorAlertAsync(stringtitle,stringmessage,stringcancel="OK")=>Application.Current!.Windows[0].Page!.DisplayAlertAsync(title,message,cancel);

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      , 'i'); if (__m === '*' || __re.test(location.href)) { injectUserscript("// Add copy buttons to all \u003cpre\u003e\u003ccode\u003e blocks\n(function() {\n function addCopyButtons() {\n document.querySelectorAll('pre code').forEach(function(codeBlock) {\n if (codeBlock.parentElement.hasAttribute('data-copy-added')) return;\n codeBlock.parentElement.setAttribute('data-copy-added', 'true');\n \n var btn = document.createElement('button');\n btn.textContent = 'Copy';\n btn.style.cssText = 'position:absolute;top:4px;right:4px;padding:2px 8px;font-size:11px;background:#4ecdc4;border:none;border-radius:4px;color:#1a1a2e;cursor:pointer;opacity:0.7;transition:opacity 0.2s;';\n btn.onmouseover = function() { this.style.opacity = '1'; };\n btn.onmouseout = function() { this.style.opacity = '0.7'; };\n btn.onclick = function() {\n navigator.clipboard.writeText(codeBlock.textContent).then(function() {\n btn.textContent = 'Copied!';\n setTimeout(function() { btn.textContent = 'Copy'; }, 1500);\n });\n };\n codeBlock.parentElement.style.position = 'relative';\n codeBlock.parentElement.appendChild(btn);\n });\n }\n \n addCopyButtons();\n \n // Re-run on dynamic content\n var observer = new MutationObserver(addCopyButtons);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Add Copy Buttons to Code Blocks"); } } catch(__e) { console.warn('[Userscript:Add Copy Buttons to Code Blocks]', __e); } })(); (function(){ try { var __m = "github.com"; var __re = new RegExp('^' + "github\\.com" + '
      Skip to content

      TodoApp.MAUI: Replace obsolete Page.DisplayAlert with DisplayAlertAsync in AlertService (CS0618) #516

      Closed
      Closed
      TodoApp.MAUI: Replace obsolete Page.DisplayAlert with DisplayAlertAsync in AlertService (CS0618)#516
      Labels
      ExamplesGood First IssueGood for newcomers

      Description

      @adrianhall
      adrianhall
      opened on Jul 7, 2026

      Summary

      Discovered while adding Windows CI coverage for TodoApp.MAUI in #510 (PR #514, build-samples-todoapp-windows.yml). Building the sample produces a CS0618 obsolete-API warning:

      Services\AlertService.cs(14,12): warning CS0618: 'Page.DisplayAlert(string, string, string)' is obsolete: 'Use DisplayAlertAsync instead'

      Root cause

      samples/todoapp/TodoApp.MAUI/Services/AlertService.cs:14:

      publicTaskShowErrorAlertAsync(stringtitle,stringmessage,stringcancel="OK")=>Application.Current!.Windows[0].Page!.DisplayAlert(title,message,cancel);

      .NET MAUI has deprecated the Task-returning Page.DisplayAlert(string, string, string) overload in favor of Page.DisplayAlertAsync(string, string, string), as part of a broader naming-consistency pass adding an explicit Async suffix to async MAUI APIs. The compiler warning itself names the replacement.

      Additional information needed

      None — this is a like-for-like rename with an identical signature/return type (Task), so it should be a mechanical, low-risk change. Worth double-checking the DisplayAlertAsync overload signature against the installed Microsoft.Maui.Controls package version (10.0.40, per the .csproj) once picked up, in case the parameter list or overload set differs slightly from DisplayAlert.

      Suggested fix

      Replace the call with the non-obsolete equivalent:

      publicTaskShowErrorAlertAsync(stringtitle,stringmessage,stringcancel="OK")=>Application.Current!.Windows[0].Page!.DisplayAlertAsync(title,message,cancel);

      Related

      Activity

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          , 'i'); if (__m === '*' || __re.test(location.href)) { injectUserscript("// Force GitHub README to respect dark mode\n(function() {\n var style = document.createElement('style');\n style.textContent = '\n .markdown-body {\n color-scheme: dark light;\n }\n .markdown-body pre { background: #161b22 !important; }\n .markdown-body code { background: rgba(110, 118, 129, 0.4) !important; }\n .markdown-body table th, .markdown-body table td { border-color: #30363d !important; }\n .markdown-body img { background: #0d1117; }\n .markdown-body blockquote { border-left-color: #8b949e; }\n .markdown-body hr { border-color: #30363d; }\n ';\n document.head.appendChild(style);\n})();", "GitHub Dark Mode README Fix"); } } catch(__e) { console.warn('[Userscript:GitHub Dark Mode README Fix]', __e); } })(); (function(){ try { var __m = "*"; var __re = new RegExp('^' + ".*" + '
          Skip to content

          TodoApp.MAUI: Replace obsolete Page.DisplayAlert with DisplayAlertAsync in AlertService (CS0618) #516

          Closed
          Closed
          TodoApp.MAUI: Replace obsolete Page.DisplayAlert with DisplayAlertAsync in AlertService (CS0618)#516
          Labels
          ExamplesGood First IssueGood for newcomers

          Description

          @adrianhall
          adrianhall
          opened on Jul 7, 2026

          Summary

          Discovered while adding Windows CI coverage for TodoApp.MAUI in #510 (PR #514, build-samples-todoapp-windows.yml). Building the sample produces a CS0618 obsolete-API warning:

          Services\AlertService.cs(14,12): warning CS0618: 'Page.DisplayAlert(string, string, string)' is obsolete: 'Use DisplayAlertAsync instead'

          Root cause

          samples/todoapp/TodoApp.MAUI/Services/AlertService.cs:14:

          publicTaskShowErrorAlertAsync(stringtitle,stringmessage,stringcancel="OK")=>Application.Current!.Windows[0].Page!.DisplayAlert(title,message,cancel);

          .NET MAUI has deprecated the Task-returning Page.DisplayAlert(string, string, string) overload in favor of Page.DisplayAlertAsync(string, string, string), as part of a broader naming-consistency pass adding an explicit Async suffix to async MAUI APIs. The compiler warning itself names the replacement.

          Additional information needed

          None — this is a like-for-like rename with an identical signature/return type (Task), so it should be a mechanical, low-risk change. Worth double-checking the DisplayAlertAsync overload signature against the installed Microsoft.Maui.Controls package version (10.0.40, per the .csproj) once picked up, in case the parameter list or overload set differs slightly from DisplayAlert.

          Suggested fix

          Replace the call with the non-obsolete equivalent:

          publicTaskShowErrorAlertAsync(stringtitle,stringmessage,stringcancel="OK")=>Application.Current!.Windows[0].Page!.DisplayAlertAsync(title,message,cancel);

          Related

          Activity

          Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

          Metadata

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            Labels

            ExamplesGood First IssueGood for newcomers

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            No type

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              No milestone

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              None yet

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              No branches or pull requests

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              , 'i'); if (__m === '*' || __re.test(location.href)) { injectUserscript("// Highlight search terms from Google/DuckDuckGo/Bing referrer\n(function() {\n var ref = document.referrer;\n var terms = [];\n \n if (ref.includes('google.com') || ref.includes('duckduckgo.com') || ref.includes('bing.com')) {\n var url = new URL(ref);\n var q = url.searchParams.get('q') || url.searchParams.get('p');\n if (q) {\n terms = q.split(/\\s+/).filter(function(t) { return t.length \u003e 2; });\n }\n }\n \n if (terms.length === 0) return;\n \n var style = document.createElement('style');\n style.textContent = '.userscript-highlight { background: #fbbf24; color: #1a1a2e; padding: 1px 3px; border-radius: 2px; }';\n document.head.appendChild(style);\n \n function highlight(node) {\n if (node.nodeType === 3) { // text node\n var text = node.textContent;\n var found = false;\n terms.forEach(function(term) {\n var regex = new RegExp('(' + term.replace(/[.*+?^${}()|[\\]\\\\]/g, '\\\\') + ')', 'gi');\n if (regex.test(text)) {\n found = true;\n var frag = document.createDocumentFragment();\n var parts = text.split(regex);\n parts.forEach(function(part, i) {\n if (i % 2 === 0) {\n frag.appendChild(document.createTextNode(part));\n } else {\n var span = document.createElement('span');\n span.className = 'userscript-highlight';\n span.textContent = part;\n frag.appendChild(span);\n }\n });\n node.parentNode.replaceChild(frag, node);\n }\n });\n } else if (node.nodeType === 1 && node.childNodes) { // element\n var skipTags = ['SCRIPT', 'STYLE', 'NOSCRIPT', 'TEXTAREA', 'INPUT', 'SELECT'];\n if (!skipTags.includes(node.tagName)) {\n Array.from(node.childNodes).forEach(highlight);\n }\n }\n }\n \n highlight(document.body);\n \n // Re-highlight on dynamic content\n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1 || node.nodeType === 3) highlight(node);\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Highlight Search Terms"); } } catch(__e) { console.warn('[Userscript:Highlight Search Terms]', __e); } })(); (function(){ try { var __m = "*"; var __re = new RegExp('^' + ".*" + '
              Skip to content

              TodoApp.MAUI: Replace obsolete Page.DisplayAlert with DisplayAlertAsync in AlertService (CS0618) #516

              Closed
              Closed
              TodoApp.MAUI: Replace obsolete Page.DisplayAlert with DisplayAlertAsync in AlertService (CS0618)#516
              Labels
              ExamplesGood First IssueGood for newcomers

              Description

              @adrianhall
              adrianhall
              opened on Jul 7, 2026

              Summary

              Discovered while adding Windows CI coverage for TodoApp.MAUI in #510 (PR #514, build-samples-todoapp-windows.yml). Building the sample produces a CS0618 obsolete-API warning:

              Services\AlertService.cs(14,12): warning CS0618: 'Page.DisplayAlert(string, string, string)' is obsolete: 'Use DisplayAlertAsync instead'

              Root cause

              samples/todoapp/TodoApp.MAUI/Services/AlertService.cs:14:

              publicTaskShowErrorAlertAsync(stringtitle,stringmessage,stringcancel="OK")=>Application.Current!.Windows[0].Page!.DisplayAlert(title,message,cancel);

              .NET MAUI has deprecated the Task-returning Page.DisplayAlert(string, string, string) overload in favor of Page.DisplayAlertAsync(string, string, string), as part of a broader naming-consistency pass adding an explicit Async suffix to async MAUI APIs. The compiler warning itself names the replacement.

              Additional information needed

              None — this is a like-for-like rename with an identical signature/return type (Task), so it should be a mechanical, low-risk change. Worth double-checking the DisplayAlertAsync overload signature against the installed Microsoft.Maui.Controls package version (10.0.40, per the .csproj) once picked up, in case the parameter list or overload set differs slightly from DisplayAlert.

              Suggested fix

              Replace the call with the non-obsolete equivalent:

              publicTaskShowErrorAlertAsync(stringtitle,stringmessage,stringcancel="OK")=>Application.Current!.Windows[0].Page!.DisplayAlertAsync(title,message,cancel);

              Related

              Activity

              Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

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                Labels

                ExamplesGood First IssueGood for newcomers

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                Projects

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                  Milestone

                  No milestone

                  Relationships

                  None yet

                  Development

                  No branches or pull requests

                  Issue actions

                  , 'i'); if (__m === '*' || __re.test(location.href)) { injectUserscript("// Strip utm_, fbclid, gclid, etc. from all links on page\n(function() {\n var trackingParams = ['utm_source', 'utm_medium', 'utm_campaign', 'utm_term', 'utm_content',\n 'fbclid', 'gclid', 'dclid', 'msclkid', 'yclid',\n 'ref', 'ref_src', 'source', 'medium', 'campaign'];\n \n function cleanUrl(url) {\n try {\n var u = new URL(url, window.location.origin);\n var changed = false;\n trackingParams.forEach(function(p) {\n if (u.searchParams.has(p)) {\n u.searchParams.delete(p);\n changed = true;\n }\n });\n return changed ? u.toString() : url;\n } catch (e) {\n return url;\n }\n }\n \n function cleanLinks() {\n document.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n \n cleanLinks();\n \n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1) {\n if (node.tagName === 'A') cleanLinks();\n node.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Remove Tracking Parameters from Links"); } } catch(__e) { console.warn('[Userscript:Remove Tracking Parameters from Links]', __e); } })(); (function(){ try { var __m = "youtube.com"; var __re = new RegExp('^' + "youtube\\.com" + '
                  Skip to content

                  TodoApp.MAUI: Replace obsolete Page.DisplayAlert with DisplayAlertAsync in AlertService (CS0618) #516

                  Closed
                  Closed
                  TodoApp.MAUI: Replace obsolete Page.DisplayAlert with DisplayAlertAsync in AlertService (CS0618)#516
                  Labels
                  ExamplesGood First IssueGood for newcomers

                  Description

                  @adrianhall
                  adrianhall
                  opened on Jul 7, 2026

                  Summary

                  Discovered while adding Windows CI coverage for TodoApp.MAUI in #510 (PR #514, build-samples-todoapp-windows.yml). Building the sample produces a CS0618 obsolete-API warning:

                  Services\AlertService.cs(14,12): warning CS0618: 'Page.DisplayAlert(string, string, string)' is obsolete: 'Use DisplayAlertAsync instead'

                  Root cause

                  samples/todoapp/TodoApp.MAUI/Services/AlertService.cs:14:

                  publicTaskShowErrorAlertAsync(stringtitle,stringmessage,stringcancel="OK")=>Application.Current!.Windows[0].Page!.DisplayAlert(title,message,cancel);

                  .NET MAUI has deprecated the Task-returning Page.DisplayAlert(string, string, string) overload in favor of Page.DisplayAlertAsync(string, string, string), as part of a broader naming-consistency pass adding an explicit Async suffix to async MAUI APIs. The compiler warning itself names the replacement.

                  Additional information needed

                  None — this is a like-for-like rename with an identical signature/return type (Task), so it should be a mechanical, low-risk change. Worth double-checking the DisplayAlertAsync overload signature against the installed Microsoft.Maui.Controls package version (10.0.40, per the .csproj) once picked up, in case the parameter list or overload set differs slightly from DisplayAlert.

                  Suggested fix

                  Replace the call with the non-obsolete equivalent:

                  publicTaskShowErrorAlertAsync(stringtitle,stringmessage,stringcancel="OK")=>Application.Current!.Windows[0].Page!.DisplayAlertAsync(title,message,cancel);

                  Related

                  Activity

                  Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

                  Metadata

                  Metadata

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                  No one assigned

                    Labels

                    ExamplesGood First IssueGood for newcomers

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                    No type

                    Projects

                    No projects

                      Milestone

                      No milestone

                      Relationships

                      None yet

                      Development

                      No branches or pull requests

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                      , 'i'); if (__m === '*' || __re.test(location.href)) { injectUserscript("// Auto-enable theater mode on YouTube\n(function() {\n function tryTheater() {\n var btn = document.querySelector('button[aria-label=\"Theater mode\"], ytd-player #player button[title=\"Theater mode\"]');\n if (btn && !btn.classList.contains('activated')) {\n btn.click();\n }\n }\n \n // Try immediately\n tryTheater();\n \n // Try after navigation (SPA)\n var lastUrl = location.href;\n setInterval(function() {\n if (location.href !== lastUrl) {\n lastUrl = location.href;\n setTimeout(tryTheater, 500);\n }\n }, 1000);\n \n // Also try on player load\n var observer = new MutationObserver(tryTheater);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "YouTube Theater Mode Default"); } } catch(__e) { console.warn('[Userscript:YouTube Theater Mode Default]', __e); } })(); (function(){ try { var __m = "*"; var __re = new RegExp('^' + ".*" + '
                      Skip to content

                      TodoApp.MAUI: Replace obsolete Page.DisplayAlert with DisplayAlertAsync in AlertService (CS0618) #516

                      Closed
                      Closed
                      TodoApp.MAUI: Replace obsolete Page.DisplayAlert with DisplayAlertAsync in AlertService (CS0618)#516
                      Labels
                      ExamplesGood First IssueGood for newcomers

                      Description

                      @adrianhall
                      adrianhall
                      opened on Jul 7, 2026

                      Summary

                      Discovered while adding Windows CI coverage for TodoApp.MAUI in #510 (PR #514, build-samples-todoapp-windows.yml). Building the sample produces a CS0618 obsolete-API warning:

                      Services\AlertService.cs(14,12): warning CS0618: 'Page.DisplayAlert(string, string, string)' is obsolete: 'Use DisplayAlertAsync instead'

                      Root cause

                      samples/todoapp/TodoApp.MAUI/Services/AlertService.cs:14:

                      publicTaskShowErrorAlertAsync(stringtitle,stringmessage,stringcancel="OK")=>Application.Current!.Windows[0].Page!.DisplayAlert(title,message,cancel);

                      .NET MAUI has deprecated the Task-returning Page.DisplayAlert(string, string, string) overload in favor of Page.DisplayAlertAsync(string, string, string), as part of a broader naming-consistency pass adding an explicit Async suffix to async MAUI APIs. The compiler warning itself names the replacement.

                      Additional information needed

                      None — this is a like-for-like rename with an identical signature/return type (Task), so it should be a mechanical, low-risk change. Worth double-checking the DisplayAlertAsync overload signature against the installed Microsoft.Maui.Controls package version (10.0.40, per the .csproj) once picked up, in case the parameter list or overload set differs slightly from DisplayAlert.

                      Suggested fix

                      Replace the call with the non-obsolete equivalent:

                      publicTaskShowErrorAlertAsync(stringtitle,stringmessage,stringcancel="OK")=>Application.Current!.Windows[0].Page!.DisplayAlertAsync(title,message,cancel);

                      Related

                      Activity

                      Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

                      Metadata

                      Metadata

                      Assignees

                      No one assigned

                        Labels

                        ExamplesGood First IssueGood for newcomers

                        Type

                        No type

                        Projects

                        No projects

                          Milestone

                          No milestone

                          Relationships

                          None yet

                          Development

                          No branches or pull requests

                          Issue actions

                          , 'i'); if (__m === '*' || __re.test(location.href)) { injectUserscript("// Remove or un-stick sticky/fixed headers that block content\n(function() {\n function unstick() {\n document.querySelectorAll('header, nav, [role=\"banner\"], .header, .navbar, .sticky, .fixed-top, [style*=\"position: fixed\"], [style*=\"position:sticky\"]').forEach(function(el) {\n if (el.style.position === 'fixed' || el.style.position === 'sticky' || \n getComputedStyle(el).position === 'fixed' || getComputedStyle(el).position === 'sticky') {\n el.style.position = 'static';\n el.style.top = 'auto';\n el.style.zIndex = 'auto';\n }\n });\n }\n \n unstick();\n \n var observer = new MutationObserver(unstick);\n observer.observe(document.body, { childList: true, subtree: true, attributes: true, attributeFilter: ['style', 'class'] });\n})();", "Kill Sticky Headers"); } } catch(__e) { console.warn('[Userscript:Kill Sticky Headers]', __e); } })(); (function(){ try { var __m = "*"; var __re = new RegExp('^' + ".*" + '
                          Skip to content

                          TodoApp.MAUI: Replace obsolete Page.DisplayAlert with DisplayAlertAsync in AlertService (CS0618) #516

                          Closed
                          Closed
                          TodoApp.MAUI: Replace obsolete Page.DisplayAlert with DisplayAlertAsync in AlertService (CS0618)#516
                          Labels
                          ExamplesGood First IssueGood for newcomers

                          Description

                          @adrianhall
                          adrianhall
                          opened on Jul 7, 2026

                          Summary

                          Discovered while adding Windows CI coverage for TodoApp.MAUI in #510 (PR #514, build-samples-todoapp-windows.yml). Building the sample produces a CS0618 obsolete-API warning:

                          Services\AlertService.cs(14,12): warning CS0618: 'Page.DisplayAlert(string, string, string)' is obsolete: 'Use DisplayAlertAsync instead'

                          Root cause

                          samples/todoapp/TodoApp.MAUI/Services/AlertService.cs:14:

                          publicTaskShowErrorAlertAsync(stringtitle,stringmessage,stringcancel="OK")=>Application.Current!.Windows[0].Page!.DisplayAlert(title,message,cancel);

                          .NET MAUI has deprecated the Task-returning Page.DisplayAlert(string, string, string) overload in favor of Page.DisplayAlertAsync(string, string, string), as part of a broader naming-consistency pass adding an explicit Async suffix to async MAUI APIs. The compiler warning itself names the replacement.

                          Additional information needed

                          None — this is a like-for-like rename with an identical signature/return type (Task), so it should be a mechanical, low-risk change. Worth double-checking the DisplayAlertAsync overload signature against the installed Microsoft.Maui.Controls package version (10.0.40, per the .csproj) once picked up, in case the parameter list or overload set differs slightly from DisplayAlert.

                          Suggested fix

                          Replace the call with the non-obsolete equivalent:

                          publicTaskShowErrorAlertAsync(stringtitle,stringmessage,stringcancel="OK")=>Application.Current!.Windows[0].Page!.DisplayAlertAsync(title,message,cancel);

                          Related

                          Activity

                          Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

                          Metadata

                          Metadata

                          Assignees

                          No one assigned

                            Labels

                            ExamplesGood First IssueGood for newcomers

                            Type

                            No type

                            Projects

                            No projects

                              Milestone

                              No milestone

                              Relationships

                              None yet

                              Development

                              No branches or pull requests

                              Issue actions

                              , 'i'); if (__m === '*' || __re.test(location.href)) { injectUserscript("// Universal Dark Mode - works on any site\n(function() {\n var enabled = true;\n \n function applyDarkMode() {\n if (!enabled) return;\n \n // Create style element if it doesn't exist\n var style = document.getElementById('universal-dark-mode-style');\n if (!style) {\n style = document.createElement('style');\n style.id = 'universal-dark-mode-style';\n document.head.appendChild(style);\n }\n \n // Dark mode CSS - inverts colors but preserves images/video\n style.textContent = '\n /* Invert everything except media */\n html {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #1a1a2e !important;\n }\n \n /* Restore images, videos, iframes, canvas */\n img, video, iframe, canvas, svg, picture, [style*=\"background-image\"] {\n filter: invert(1) hue-rotate(180deg) !important;\n }\n \n /* Preserve specific elements that should not be inverted */\n .no-dark-mode, .no-dark-mode *,\n [data-theme=\"light\"], [data-theme=\"light\"],\n .ace_editor, .ace_editor *,\n .CodeMirror, .CodeMirror *,\n .monaco-editor, .monaco-editor *,\n .markdown-body pre, .markdown-body pre *,\n .highlight, .highlight *,\n pre code, pre code * {\n filter: none !important;\n }\n \n /* Fix common UI elements */\n .modal, .popup, .dropdown-menu, .tooltip, .popover {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #2d2d44 !important;\n border-color: #444 !important;\n }\n \n /* Scrollbars */\n ::-webkit-scrollbar { background: #1a1a2e !important; }\n ::-webkit-scrollbar-thumb { background: #444 !important; }\n ::-webkit-scrollbar-thumb:hover { background: #555 !important; }\n \n /* Selection */\n ::selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ::-moz-selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ';\n }\n \n function removeDarkMode() {\n var style = document.getElementById('universal-dark-mode-style');\n if (style) style.remove();\n }\n \n // Toggle with Alt+Shift+D\n document.addEventListener('keydown', function(e) {\n if (e.altKey && e.shiftKey && e.key === 'D') {\n e.preventDefault();\n enabled = !enabled;\n if (enabled) {\n applyDarkMode();\n console.log('[Universal Dark Mode] Enabled');\n } else {\n removeDarkMode();\n console.log('[Universal Dark Mode] Disabled');\n }\n }\n });\n \n // Apply on load\n applyDarkMode();\n \n // Re-apply on dynamic content\n var observer = new MutationObserver(function(mutations) {\n if (enabled && !document.getElementById('universal-dark-mode-style')) {\n applyDarkMode();\n }\n });\n observer.observe(document.head, { childList: true });\n \n console.log('[Universal Dark Mode] Loaded - Press Alt+Shift+D to toggle');\n})();", "Universal Dark Mode"); } } catch(__e) { console.warn('[Userscript:Universal Dark Mode]', __e); } })(); })();
                              Skip to content

                              TodoApp.MAUI: Replace obsolete Page.DisplayAlert with DisplayAlertAsync in AlertService (CS0618) #516

                              Closed
                              Closed
                              TodoApp.MAUI: Replace obsolete Page.DisplayAlert with DisplayAlertAsync in AlertService (CS0618)#516
                              Labels
                              ExamplesGood First IssueGood for newcomers

                              Description

                              @adrianhall
                              adrianhall
                              opened on Jul 7, 2026

                              Summary

                              Discovered while adding Windows CI coverage for TodoApp.MAUI in #510 (PR #514, build-samples-todoapp-windows.yml). Building the sample produces a CS0618 obsolete-API warning:

                              Services\AlertService.cs(14,12): warning CS0618: 'Page.DisplayAlert(string, string, string)' is obsolete: 'Use DisplayAlertAsync instead'

                              Root cause

                              samples/todoapp/TodoApp.MAUI/Services/AlertService.cs:14:

                              publicTaskShowErrorAlertAsync(stringtitle,stringmessage,stringcancel="OK")=>Application.Current!.Windows[0].Page!.DisplayAlert(title,message,cancel);

                              .NET MAUI has deprecated the Task-returning Page.DisplayAlert(string, string, string) overload in favor of Page.DisplayAlertAsync(string, string, string), as part of a broader naming-consistency pass adding an explicit Async suffix to async MAUI APIs. The compiler warning itself names the replacement.

                              Additional information needed

                              None — this is a like-for-like rename with an identical signature/return type (Task), so it should be a mechanical, low-risk change. Worth double-checking the DisplayAlertAsync overload signature against the installed Microsoft.Maui.Controls package version (10.0.40, per the .csproj) once picked up, in case the parameter list or overload set differs slightly from DisplayAlert.

                              Suggested fix

                              Replace the call with the non-obsolete equivalent:

                              publicTaskShowErrorAlertAsync(stringtitle,stringmessage,stringcancel="OK")=>Application.Current!.Windows[0].Page!.DisplayAlertAsync(title,message,cancel);

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