[英]Drag and Drop one control to another control in winform
我做的事情非常非常簡單。
我有一個列表框,其事件設置如下:
public Form1()
{
InitializeComponent();
this.listBox1.AllowDrop = true;
this.listBox1.DragEnter += new DragEventHandler(listBox1_DragEnter);
this.listBox1.DragDrop += new DragEventHandler(listBox1_DragDrop);
}
void listBox1_DragDrop(object sender, DragEventArgs e)
{
//code to add labelText to Items of ListBox
}
void listBox1_DragEnter(object sender, DragEventArgs e)
{
//set DragDropEffects;
}
現在我有一個標簽,其代碼如下:
private void label1_MouseDown(object sender, MouseEventArgs e)
{
DoDragDrop((sender as Label).Text, DragDropEffects.Copy);
//this.label1.DoDragDrop((sender as Label).Text, DragDropEffects.Copy);
//used one of them at a time.
}
但什么也沒發生。 列表框DragEnter事件從不觸發。 實際上,拖曳永遠不會發生。 每當我嘗試拖動標簽(文本)時,出現不允許的Windows光標,而不是' DragDropEffects.Copy
的光標
拖放不會發生。
當我修改列表框(及其關聯的代碼)以接受要從任何其他窗口拖放到其上的文件時,效果很好。
so..am無法執行從窗體上保留的控件到同一窗體上另一個控件的拖動。
我錯過了什么嗎? 正在運行Windows XP。
請幫忙...
您的代碼確實可以正常工作。 您只需要在事件處理程序中設置正確的拖動效果即可。
void listBox1_DragDrop(object sender, DragEventArgs e)
{
e.Effect = DragDropEffects.Copy;
}
void listBox1_DragEnter(object sender, DragEventArgs e)
{
e.Effect = DragDropEffects.Copy;
}
檢查ListBox.AllowDrop是否設置為TRUE
以下是所有代碼的示例(將其添加到此處的人員)。
#region Initial Values
//Constructor:
public Form1() {
InitializeComponent();
}
private void Form1_Load( object sender, EventArgs e ) {
InitialValues();
}
private void InitialValues() {
PrepareDragAndDrop();
}
#endregion Initial Values
#region Drag & Drop
private void PrepareDragAndDrop() {
//For the object that receives the other dragged element:
TheSamplListBox.AllowDrop = true;
TheSamplListBox.DragEnter += TheSamplListBox_DragEnter;
TheSamplListBox.DragLeave += TheSamplListBox_DragLeave;
TheSamplListBox.DragDrop += TheSamplListBox_DragDrop;
//For the object that will be dragged:
TheSampleLabel.MouseDown += ( sender, args ) => DoDragDrop( TheSampleLabel.Text, DragDropEffects.Copy );
}
private void TheSamplListBox_DragEnter( object theReceiver, DragEventArgs theEventData ) {
theEventData.Effect = DragDropEffects.Copy;
//Only the code above is strictly for the Drag & Drop. The following is for user feedback:
//You can use [TheSamplListBox] but this approach allows for multiple receivers of the same type:
var theReceiverListBox = (ListBox) theReceiver;
theReceiverListBox.BackColor = Color.LightSteelBlue;
}
private void TheSamplListBox_DragLeave( object theReceiver, EventArgs theEventData ) {
//No code here for the Drag & Drop. The following is for user feedback:
//You can use [TheSamplListBox] but this approach allows for multiple receivers of the same type:
var theReceiverListBox = (ListBox) theReceiver;
theReceiverListBox.BackColor = Color.White;
}
private void TheSamplListBox_DragDrop( object theReceiver, DragEventArgs theEventData ) {
//You can use [TheSamplListBox] but this approach allows for multiple receivers of the same type:
var theReceiverListBox = (ListBox) theReceiver;
//Get the data being dropped. In this case, a string:
var theStringBeingDropped = theEventData.Data.GetData( "System.String" );
//Add the string to the ListBox:
theReceiverListBox.Items.Add( theStringBeingDropped );
//Only the code above is strictly for the Drag & Drop. The following is for user feedback:
theReceiverListBox.BackColor = Color.White;
}
#endregion Drag & Drop
。
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