Min and max binding - wpf

Question

I have two text boxes: min and max for user to enter. If the max number is smaller than the min number, the number in the max text box will be automatically changed to the same number as the min number in the min text box.
What is the best way to implement it with wpf and C#? Code would be great.
Thanks!

Answer 1

Define two properties MinValue and MaxValue of type int in your ViewModel (if using MVVM) and bind to two text boxes.
C#
private int minValue;
private int maxValue;
public int MinValue
{
get { return minValue; }
set
{
minValue = value;
PropertyChanged(this, new PropertyChangedEventArgs("MinValue"));
if (minValue > maxValue)
{
MaxValue = minValue;
}
}
}
public int MaxValue
{
get { return maxValue; }
set
{
maxValue = value;
PropertyChanged(this, new PropertyChangedEventArgs("MaxValue"));
if(maxValue < minValue)
{
MinValue = maxValue;
}
}
}
Xaml:
<TextBox Text="{Binding MinValue, UpdateSourceTrigger=PropertyChanged}"/>
<TextBox Text="{Binding MaxValue, UpdateSourceTrigger=PropertyChanged}"/>
Thanks

Answer 2

Just putting the way I achieve in my WPF code for MIN numeric Value is 0 and MAX numeric value is 99.
hope this may help
<!-- WPF Code Sample.xaml -->
<TextBox
Text="1"
Width="20"
PreviewTextInput="PreviewTextInputHandler"
IsEnabled="True"/>
https://social.msdn.microsoft.com/Forums/vstudio/en-US/990c635a-c14e-4614-b7e6-65471b0e0e26/how-to-set-minvalue-and-max-value-for-a-testbox-in-wpf?forum=wpf
// C# Code Sample.xaml.cs
private void PreviewTextInputHandler(object sender, TextCompositionEventArgs e)
{
// MIN Value is 0 and MAX value is 99
var textBox = sender as TextBox;
bool bFlag = false;
if (!string.IsNullOrWhiteSpace(e.Text) && !string.IsNullOrWhiteSpace(textBox.Text))
{
string str = textBox.Text + e.Text;
bFlag = str.Length <= 2 ? false : true;
}
e.Handled = (Regex.IsMatch(e.Text, "[^0-9]+") || bFlag);
}