Numeric Textbox Overview

The Numeric Textbox component allows the user to enter decimal values and no text. The developer can control minimum, maximum values, steps and other elements of the UX.

To use a Telerik Numeric Textbox for Blazor, add the TelerikNumericTextBox tag.

Basic numeric textbox with its key features

The new value is: @theValue

<TelerikNumericTextBox Format="C" Max="5m" Min="-5m" Step="0.33m" @bind-Value="@theValue"></TelerikNumericTextBox>

@code {
     private decimal theValue { get; set; } = 1.234m;
}

The numeric textbox component is generic, meaning that it takes the type of its value parameter as an argument. It can take int, long, float, double and decimal values. Therefore, the values for the Min, Max and Step properties must be of the same type as the Value, and the ValueChanged handler must also accommodate the corresponding value type.

Component namespace and reference

@using Telerik.Blazor.Components

<TelerikNumericTextBox @ref="myNumericTextboxRef" @bind-Value="CurrentValue"></TelerikNumericTextBox>

@code {
    //determines the type of the component
    private int CurrentValue { get; set; }

    //the type of the value variable determines the type of the reference
    private Telerik.Blazor.Components.TelerikNumericTextBox<int> myNumericTextboxRef;
}

The numeric textbox provides the following features:

  • Arrows - whether the up/down spinner arrows (buttons) will be shown. Defaults to true.
  • Decimals - how many decimal places will be allowed while the user is typing a new value. Takes effect only while the input is focused.
  • Format - the format with which the number is presented when the input is not focused. Read more in the Standard Numeric Format Strings in .NET article.
  • Max - the maximum decimal value the input can take. Must be of the same type as the Value.
  • Min - the minimum decimal value the input can take. Must be of the same type as the Value.
  • Step - the decimal value of the step with which the value changes when the arrows are used. Must be of the same type as the Value.
  • Text - getter for the original user input.
  • Value - to get/set the value of the input.
  • Validation - see the Input Validation article.

Example of using a custom format string

<TelerikNumericTextBox Format="#.00 kg" Max="5m" Min="-5m" Step="0.33m" Value="3.456789m"></TelerikNumericTextBox>

The decimal separator is . for the time being. When localization features get implemented in the Telerik UI for Blazor suite, it will be possible to take it from the current thread culture. This means that cultures with a differet separator may not funcion correctly. Currency symbols are also rendered by the framework and they come from the current culture as well.

For the time being, you can set the Blazor app culture in Program.cs like this:

public static void Main(string[] args)
{
    //this no longer works
    //System.Threading.Thread.CurrentThread.CurrentCulture = new System.Globalization.CultureInfo("en-US");

    //you have to set defaults now
    var culture = new System.Globalization.CultureInfo("en-US");
    System.Globalization.CultureInfo.DefaultThreadCurrentCulture = culture;
    System.Globalization.CultureInfo.DefaultThreadCurrentUICulture = culture;

    CreateHostBuilder(args).Build().Run();
}

See Also

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