#Javascript run as soon as element renders code
If it sees one, it jumps out of code and will only jump back into code when it sees a matching closing tag: numbers = Enumerable. Range(1, 10) //Get numbers from 1 - 10įoreach ( var number in number * 10 * 10 = number * 10 ) You only need to use the operator once per line: numbers = Enumerable. Range(1, 10) //Get numbers from 1 - 10įoreach ( var number in number * 10 The first, if the additional item is text only, is to prefix the text with before the first instance of text in the line: numbers = Enumerable. If you want to mix inline variables with items to be rendered literally (verbatim strings) within a code block, there are three ways to tell Razor where the code pauses and the literal text or markup begins. If you want to render the result of a single line expression, you use the. If you want to render the variable number within the loop above, you have to prefix it with an sign: numbers = Enumerable. Everything that follows is assumed to be code, unless you tell Razor otherwise: numbers = Enumerable. As soon as you type you are assumed to have started writing code. The code doesn't create an infinite loop because StateHasChanged is only called when data is null.All code blocks must appear within. StateHasChanged is called to rerender the component with the new state obtained from the JS interop call (for more information, see ASP.NET Core Razor component rendering). Where JSRuntime.InvokeAsync is called, the ElementReference is only used in OnAfterRenderAsync and not in any earlier lifecycle method because there's no JS element until after the component is rendered. For more information, see ASP.NET Core Blazor JavaScript interoperability (JS interop).
Directly modifying the DOM with JS isn't recommended in most scenarios because JS can interfere with Blazor's change tracking.
The preceding example modifies the Document Object Model (DOM) directly for demonstration purposes only. The function is called with JSRuntimeExtensions.InvokeVoidAsync and doesn't return a value. While an app is prerendering, certain actions, such as calling into JavaScript (JS), aren't possible.įor the following example, the setElementText1 function is placed inside the element. Prerendering is covered in Prerender and integrate ASP.NET Core Razor components. This section applies to Blazor Server and hosted Blazor WebAssembly apps that prerender Razor components. Public void Dispose() => jsClass?.Dispose() įor dynamic content generation with BuildRenderTree, use the attribute: The JS function accepts a byte array from a C# method, decodes the array, and returns the text to the component for display.
#Javascript run as soon as element renders how to
The example demonstrates how to invoke a JS function from a C# method that offloads a requirement from developer code to an existing JS API. The following example is based on TextDecoder, a JS-based decoder. For more information, see the Prerendering section. InvokeAsync unwraps the Promise and returns the value awaited by the Promise.įor Blazor apps with prerendering enabled, calling into JS isn't possible during prerendering. A JS Promise is returned for InvokeAsync methods.
NET type that best maps to the JSON type returned. The TValue return type must also be JSON serializable.TimeSpan represents a time limit for a JS operation.The cancellation token ( CancellationToken) propagates a notification that operations should be canceled.Pass any number of JSON-serializable arguments in Object to a JS function.There's no need to register the function before it's called. To call, the identifier is someScope.someFunction. The function identifier ( String) is relative to the global scope ( window).NET, inject the IJSRuntime abstraction and call one of the following methods:įor the preceding. IJSRuntime is registered by the Blazor framework. NET methods from JavaScript functions in ASP.NET Core Blazor.