[英]How To Set ComboBox's SelectedItem Programmatically via Silverlight?
[英]How to programmatically bind a System.Windows.Controls.Parameter to a ComboBox' SelectedItem in Silverlight
我有來自 MSDN 的以下示例:
<Grid x:Name="LayoutRoot" Background="White">
<Grid.RowDefinitions>
<RowDefinition Height="25" />
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<riaControls:DomainDataSource Name="source" QueryName="GetProductsByColor" AutoLoad="true">
<riaControls:DomainDataSource.DomainContext>
<domain:ProductDomainContext />
</riaControls:DomainDataSource.DomainContext>
<riaControls:DomainDataSource.QueryParameters>
<riaControls:Parameter ParameterName="color" Value="{Binding ElementName=colorCombo, Path=SelectedItem.Content}" />
</riaControls:DomainDataSource.QueryParameters>
</riaControls:DomainDataSource>
<ComboBox Width="60" Grid.Row="0" x:Name="colorCombo">
<ComboBoxItem Content="Black" />
<ComboBoxItem Content="Blue" />
</ComboBox>
<data:DataGrid Grid.Row="1" ItemsSource="{Binding Data, ElementName=source}" />
</Grid>
好吧,如您所見,設置了創建參數綁定的行:
<riaControls:Parameter ParameterName="color" Value="{Binding ElementName=colorCombo, Path=SelectedItem.Content}" />
但是,如果我要用代碼嘗試這個,它不起作用:
Binding binding = new Binding();
binding.ElementName = "colorCombo";
//binding.Source = this.colorCombo; also doesn't work!
binding.Path = new PropertyPath("SelectedItem.Content");
binding.Mode = BindingMode.OneWay;
Parameter param = new Parameter();
param.Value = binding;
source.QueryParameters.Clear();
source.QueryParameters.Add(param);
關於我做錯了什么的任何想法?
要以編程方式綁定,您必須使用BindingOperations.SetBinding
。 目前,您只是將Value
屬性設置為Binding
實例,而不是綁定它。
BindingOperations.SetBinding(param, Parameter.ValueProperty, binding)
另外,將您的綁定改回Source = this.colorCombo
。 元素名稱通常在 XAML 上下文中解析,這在代碼隱藏中不存在。
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