Hier ein kleines Beispiel, um in C# WPF ein Button zu deaktivieren, wenn eine TextBox leer ist.
xaml – 1x Button / 1x TextBox
<TextBox x:Name="firstNameTxtBox"/>
<Button Content="Save">
<Button.Style>
<Style TargetType="{x:Type Button}">
<Style.Triggers>
<DataTrigger Binding="{Binding Text.Length, ElementName=firstNameTxtBox, UpdateSourceTrigger=PropertyChanged}" Value="0">
<Setter Property="IsEnabled" Value="False"/>
</DataTrigger>
</Style.Triggers>
</Style>
</Button.Style>
</Button>Code-Sprache: HTML, XML (xml)
xaml – 1x Button / 2x TextBox
<TextBox x:Name="firstNameTxtBox"/>
<TextBox x:Name="lastNameTxtBox"/>
<Button Content="Save">
<Button.Style>
<Style TargetType="{x:Type Button}">
<Style.Triggers>
<DataTrigger Binding="{Binding Text.Length, ElementName=firstNameTxtBox, UpdateSourceTrigger=PropertyChanged}" Value="0">
<Setter Property="IsEnabled" Value="False"/>
</DataTrigger>
<DataTrigger Binding="{Binding Text.Length, ElementName=lastNameTxtBox, UpdateSourceTrigger=PropertyChanged}" Value="0">
<Setter Property="IsEnabled" Value="False"/>
</DataTrigger>
</Style.Triggers>
</Style>
</Button.Style>
</Button>Code-Sprache: HTML, XML (xml)