Restriction or Validation in WPF Integer TextBox

18 Nov 20185 minutes to read

This section explains how to validate or restrict the WPF Integer TextBox control value.

Restrict the value within minimum and maximum value

The Value of the WPF Integer TextBox can be restricted within the maximum and minimum limits. Once the value has reached the maximum or minimum value, the value does not exceed the limit. You can change the minimum and maximum limits by using the MinValue and MaxValue properties.

You can choose when to validate the maximum and minimum limits while changing the values by using the MinValidation and MaxValidation properties.

• OnKeyPress — When MaxValidation or MinValidation is set to OnKeyPress, the value in the WPF Integer TextBox is validated shortly after pressing a key. As a result, invalid input is not allowed, and the value does not exceed the maximum and minimum limits.

• OnLostFocus - When MaxValidation or MinValidation is set to OnLostFocus, the value in the WPF Integer TextBox is validated when the control loses keyboard focus. After validation, when the value is greater than the MaxValue or less than the MinValue, the value will be automatically set to MaxValue or MinValue.

• MaxValueOnExceedMaxDigit - When you give input greater than the specified maximum limit, MaxValueOnExceedMaxDigit decides whether to retain the old value or reset to the specified maximum limit. For example, if MaxValue is set to 100 and you are trying to input 200, the Value will change to 100 when MaxValueOnExceedMaxDigit is true, or 20 will be retained if MaxValueOnExceedMaxDigit is false.

• MinValueOnExceedMinDigit - When you give input less than the specified minimum limit, MinValueOnExceedMinDigit decides whether to retain the old value or reset to the specified minimum limit. For example, if MinValue is set to 200 and the Value is 205, and you try to change the value to 20, the Value will change to 200 when MinValueOnExceedMinDigit is true, or the old value 205 will be retained if MinValueOnExceedMinDigit is false.

  NOTE

  MaxValueOnExceedMaxDigit and MinValueOnExceedMinDigit are only effective when the corresponding MaxValidation and MinValidation properties are set to OnKeyPress.

XAML

<syncfusion:IntegerTextBox x:Name="integerTextBox" Width="150" MaxValue="100" MinValue="10"
                          MinValueOnExceedMinDigit="True" MaxValueOnExceedMaxDigit="True"
                          MinValidation="OnKeyPress" MaxValidation="OnLostFocus"/>

C#

using Syncfusion.Windows.Shared;

IntegerTextBox integerTextBox = new IntegerTextBox();
integerTextBox.Width = 150;
integerTextBox.Height = 25;
integerTextBox.MinValue = 10;
integerTextBox.MaxValue = 100;
integerTextBox.MinValidation = MinValidation.OnKeyPress;
integerTextBox.MaxValidation = MaxValidation.OnLostFocus;
integerTextBox.MinValueOnExceedMinDigit = true;
integerTextBox.MaxValueOnExceedMaxDigit = true;

When MinValidation is set to OnKeyPress, you cannot enter a value less than the MinValue. If you try to enter a value less than the MinValue, the MinValue will be set to the Value property because MinValueOnExceedMinDigit is set to true.

MaxValidation is set to OnLostFocus, so the MaxValidation will be performed only on lost focus.

Read-only mode

The WPF Integer TextBox does not allow user input or edits at runtime when the IsReadOnly property is set to true. The user can still select text and display the cursor in the WPF Integer TextBox by setting the IsReadOnlyCaretVisible property to true. The default value of IsReadOnly is false and the default value of IsReadOnlyCaretVisible is false. The Value can still be changed programmatically in read-only mode.

XAML

<syncfusion:IntegerTextBox x:Name="integerTextBox" IsReadOnly="True" Value="78" IsReadOnlyCaretVisible="True"/>

C#

using Syncfusion.Windows.Shared;

IntegerTextBox integerTextBox = new IntegerTextBox();
integerTextBox.Value = 78;
integerTextBox.IsReadOnly = true;
integerTextBox.IsReadOnlyCaretVisible = true;

Customizing the Behavior for an Invalid Value

You can customize how the WPF Integer TextBox behaves when the entered value is not equal to the ValidationValue property, by using the InvalidValueBehavior property. It can be customized by the following values:

• DisplayErrorMessage - Shows a MessageBox with the message “String validation failed” after focus is lost from the WPF Integer TextBox.
• None - Validation will not occur.
• ResetValue - Resets the entered value to 0 after focus is lost.

NOTE

By default the ValidationValue property value is String.Empty. The ValidationValue is a string; the entered value is compared to it as a string.

XAML

<syncfusion:IntegerTextBox Width="120" Height="30"
                         InvalidValueBehavior="DisplayErrorMessage"
                         ValidationValue="1222"
                         VerticalAlignment="Center"
                         HorizontalAlignment="Center" />

C#

using Syncfusion.Windows.Shared;
using System.Windows;

IntegerTextBox integerTextBox = new IntegerTextBox()
{
    Height = 30,
    Width = 120,
    InvalidValueBehavior = InvalidValueBehavior.DisplayErrorMessage,
    ValidationValue = "1222",
    HorizontalAlignment = HorizontalAlignment.Center,
    VerticalAlignment = VerticalAlignment.Center
};