Restriction or Validation in WPF Percent TextBox

6 Jul 20216 minutes to read

This section explains how to validate or restrict the PercentTextBox control value.

Restrict the value within minimum and maximum value

The PercentValue of the PercentTextBox can be restricted within the maximum and minimum limits. Once the percent value has reached the maximum or minimum value , the value does not exceed the limit. We can change the maximum and minimum limits by using the MinValue property and MaxValue property.

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

• OnKeyPress — When setting the MaxValidation or MinValidation to OnKeyPress, the percent value in the PercentTextBox will be validated shortly after pressing a key. So, it is not possible to provide any invalid input at all and the percent value does not exceed the maximum and minimum limits.

• OnLostFocus - When setting MaxValidation or MinValidation to OnLostFocus, the percent value in the PercentTextBox is validated, when the PercentTextBox loses the focus. That is, the PercentTextBox will accept any percent value, validation will only take place after the PercentTextBox has lost its keyboard focus. After validation, when the percent value of the PercentTextBox is greater than the MaxValue or less than the MinValue, the percent value will be automatically set to MaxValue or MinValue.

• MaxValueOnExceedMaxDigit - When you give input greater than specified maximum limit, MaxValueOnExceedMaxDigit property will decide either it should retain the old percent value or reset to maximum limit that is specified. For example, if MaxValue is set to 100 and you are trying to input 200. PercentValue will changed to 100 when MaxValueOnExceedMaxDigit is true. When MaxValueOnExceedMaxDigit is false, 20 will be retained and last entered 0 will be ignored.

  NOTE

  MaxValueOnExceedMinDigit property will be enabled only when the MaxValidation is set to OnKeyPress.

• MinValueOnExceedMinDigit - When you give input less than specified minimum limit, MinValueOnExceedMinDigit property will decide either it should retain the old percent value or reset to minimum limit that is specified. For example, if MinValue is set to 200 and the PercentValue is 205 and you are trying change the percent value to 20. PercentValue will changed to 200 when MinValueOnExceedMinDigit is true. When MinValueOnExceedMinDigit is false, Old percent value 205 will be retained.

  NOTE

  MinValueOnExceedMinDigit will be enabled only when the MinValidation is set to OnKeyPress.

XAML

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

C#

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

MinValidation is set to OnKeyPress, it cannot let to enter a percent value less than the MinValue. If try to enter a percent value less than the MinValue, then the MinValue will set to the PercentValue property because MinValueOnExceedMinDigit is set to true.

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

Restrict number of decimal digit

You can format the decimal digits in the PercentTextBox control using PercentDecimalDigits property. You can restrict the decimal digits of text within maximum and minimum limits in PercentTextBox control using MinPercentDecimalDigits and MaxPercentDecimalDigits properties. The default value of MinPercentDecimalDigits,MaxPercentDecimalDigits and DoubleDecimalDigits properties is -1.

NOTE

If the value of MinPercentDecimalDigits property is greater than value of the MaxPercentDecimalDigits property, the text of PercentTextBox will be updated based on value of MinPercentDecimalDigits property.

XAML

<syncfusion:PercentTextBox Value="125.32545" HorizontalAlignment="Center" VerticalAlignment="Center"
                            MaxPercentDecimalDigits="4"
                            MinPercentDecimalDigits="1" />

C#

PercentTextBox percentTextBox = new PercentTextBox();
percentTextBox.Value = 125.32545;
percentTextBox.MaxPercentDecimalDigits = 4;
percentTextBox.MinPercentDecimalDigits = 1;

When the value of MinPercentDecimalDigits, MaxPercentDecimalDigits and PercentDecimalDigits properties are specified, PercentDecimalDigits property takes high precedence and updates the text of PercentTextBox property.

XAML

<syncfusion:PercentTextBox Value="125.32545" HorizontalAlignment="Center" VerticalAlignment="Center"
                            MaxPercentDecimalDigits="4"
                            MinPercentDecimalDigits="1" 
                            PercentDecimalDigits="3"
                            />

C#

PercentTextBox percentTextBox = new PercentTextBox();
percentTextBox.Value = 125.32545;
percentTextBox.MaxPercentDecimalDigits = 4;
percentTextBox.MinPercentDecimalDigits = 1;
percentTextBox.PercentDecimalDigits = 3;

Read only mode

The PercentTextBox cannot allow the user input, edits when IsReadOnly property is sets to true. The user can still select text and display the cursor on the PercentTextBox by setting the IsReadOnlyCaretVisible property to true. However, value can be changed programmatically in readonly mode.

XAML

<syncfusion:PercentTextBox x:Name="percentTextBox" IsReadOnly="True" PercentValue="10" IsReadOnlyCaretVisible="True"/>

C#

PercentTextBox percentTextBox = new PercentTextBox();
percentTextBox.PercentValue = 10;
percentTextBox.IsReadOnly = true;
percentTextBox.IsReadOnlyCaretVisible = true;