关于c＃：将一个控件拖放到winform中的另一个控件

Drag and Drop one control to another control in winform

我做的事情非常简单。

我有一个列表框，其事件设置如下：

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17

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;
}

现在我有一个标签，代码如下：

1
2
3
4
5
6
7

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.

}

号

但什么也没发生。列表框DragCenter事件从不激发。事实上，拖动从未发生过。每当我试图拖动标签(文本)时，不允许出现Windows光标，而不是"DragDropEffects.Copy的光标

不会发生拖放。

当我修改列表框(以及相关的代码)以接受从任何其他窗口放到列表框上的文件时，这是非常有效的。

因此..无法执行从窗体上保留的控件到同一窗体上保留的其他控件的拖动。

我错过什么了吗？正在运行Windows XP。

我经历过这个和这个

请帮忙…

你的代码确实有效。只需在事件处理程序中设置正确的拖动效果。

1
2
3
4
5
6
7
8
9

void listBox1_DragDrop(object sender, DragEventArgs e)
{
e.Effect = DragDropEffects.Copy;
}

void listBox1_DragEnter(object sender, DragEventArgs e)
{
e.Effect = DragDropEffects.Copy;
}

相关讨论

下面是一个您需要的示例，其中包含所有代码(为找到此文章的人添加此代码)。

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60

#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