DxMemo.TextChanging Event

Fires when a user is changing text in the editor. Use this event to validate/cancel user input.

Namespace: DevExpress.Blazor

Assembly: DevExpress.Blazor.v25.2.dll

NuGet Package: DevExpress.Blazor

Declaration

[Parameter]
public Action<ParameterValueChangingEventArgs<string>> TextChanging { get; set; }

Event Data

The TextChanging event's data class is ParameterValueChangingEventArgs<String>. The following properties provide information specific to this event:

Property	Description
NewValue	Gets or sets the new value being assigned to the parameter.
OldValue	Gets the current parameter value.

Remarks

The TextChanging event fires before a new text is applied to the editor (before the TextChanged event). You can use this event to validate/cancel user input.

In the following code, the TextChanging event handler cancels input if the text exceeds 500 characters. The current text is updated via two-way binding (@bind-Text).

<DxMemo @bind-Text="@MemoText"
        TextChanging="@OnTextChanging"
        BindValueMode="BindValueMode.OnInput">
</DxMemo>

<div class="mt-2">
    <span>Text length: @(MemoText?.Length ?? 0)</span>
</div>

@code {
    string MemoText { get; set; }

    private void OnTextChanging(ParameterValueChangingEventArgs<string> e) {
    if (e.NewValue.Length > 500) {
        e.NewValue = e.OldValue;
    }
}