ComboBox不更新所选项目上的DataBindings更改（WinForms） [英] ComboBox not updating DataBindings on selected item changed (WinForms)

问题描述

我有一个ComboBox绑定到数据源，但它不会更新绑定，直到控件失去焦点。当选择的项目更改时，如何获取绑定更新？在下面的屏幕截图中，我希望标签立即更新以反映新的选择。

一些代码：

  public enum MyEnum 
 {
首先，
 Second 
} 
 
 public class MyData 
 {
 public String Name {get;组; } 
 public MyEnum MyEnum {get;组; } 
} 
  

样本表单：

public sampleForm（）
{
InitializeComponent（）;

  
 MyData data = new MyData（）{Name =Single Item}; 
 this.bindingSource1.DataSource = data; 
 this.comboBox1.DataSource = Enum.GetValues（typeof（MyEnum））; 
 this.label2.DataBindings.Add（Text，this.bindingSource1，MyEnum，true，DataSourceUpdateMode.OnPropertyChanged）; 
 this.comboBox1.DataBindings.Add（new System.Windows.Forms.Binding（SelectedItem，this.bindingSource1，MyEnum，true））; 
 this.comboBox1.DataBindings.Add（new System.Windows.Forms.Binding（SelectedValue，this.bindingSource1，MyEnum，true））; 
} 
  

解决方案

注释出SelectedItem版本，并修改SelectedValue绑定，以包含UpdateMode：

  this.comboBox1.DataBindings.Add（new Binding（
SelectedValue，
 this.bindingSource1，
MyEnum，
 true，
 DataSourceUpdateMode.OnPropertyChanged））; 
  

I have a ComboBox bound to a data source but it will not update the bindings until the control loses focus. How can I get the bindings to update when the selected items change? In the screen shot below I'd like the label to updated immediately to reflect the new selection.

Some Code:

public enum MyEnum
{
  First,
  Second
}

public class MyData
{
  public String Name { get; set; }
  public MyEnum MyEnum { get; set; }
}  

Sample Form:

public SampleForm()
{
  InitializeComponent ();   
  MyData data = new MyData () { Name = "Single Item" };
  this.bindingSource1.DataSource = data;
  this.comboBox1.DataSource = Enum.GetValues (typeof (MyEnum));
  this.label2.DataBindings.Add ("Text", this.bindingSource1, "MyEnum", true, DataSourceUpdateMode.OnPropertyChanged);
  this.comboBox1.DataBindings.Add (new System.Windows.Forms.Binding ("SelectedItem", this.bindingSource1, "MyEnum", true));
  this.comboBox1.DataBindings.Add (new System.Windows.Forms.Binding ("SelectedValue", this.bindingSource1, "MyEnum", true));
}

解决方案

Comment out the SelectedItem version, and modify the SelectedValue binding like this to include the UpdateMode:

this.comboBox1.DataBindings.Add(new Binding(
                                      "SelectedValue",
                                      this.bindingSource1,
                                      "MyEnum",
                                      true,
                                      DataSourceUpdateMode.OnPropertyChanged));

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