問題描述

每次我想讓用戶拖動控件時，我都會調用該控件的 DoDragDrop.

Every time i want let the user to drag an control, i calling DoDragDrop of that control.

拖拽&drop 工作正常，但我對周圍的事情有疑問:

The drag & drop works fine, but i have problem with things around:

1. DoDragDrop 完全阻塞了表單，沒有計時器事件跳轉，沒有處理任何繪制消息.

1. DoDragDrop completely blocking the form, no timer events jumps, no paint messages handled.

DoDragDrop 阻止不僅用于拖動 &drop 操作，但直到目標程序完成 drop 事件(即 explorer.exe 的吸代碼).依賴其他程序的代碼很爛.

DoDragDrop blocking not only for the drag & drop operation, but until target program finishing with the drop event (I.E. explorer.exe's suck code). Depending on other program's code is sucks.

我想從一個新線程調用 DoDragDrop.

I thought to call DoDragDrop from a new thread.

試過這個:

Thread dragThread = new Thread(() =>
{
    Form frm = new Form();
    frm.DoDragDrop("data", DragDropEffects.All);
});

dragThread.SetApartmentState(ApartmentState.STA);
dragThread.IsBackground = true;
dragThread.Start();

但它似乎不起作用.我的意思是:當像這樣從其他線程執行 DoDragDrop 時，我的程序或其他程序中的其他控件不會接收拖放消息.

but it doesn't seems to work. I mean: when doing DoDragDrop from other thread like this, other controls within my program or other programs does not receiving drag&drop messages.

還有其他解決方案嗎?

推薦答案

DoDragDrop 方法會停止處理事件，直到第一個鼠標事件(例如 mouse move).所以我找到的解決方法非常簡單——你只需要在調用 DoDragDrop 之前用相同的鼠標位置模擬鼠標事件:

The DoDragDrop method stops processing of events until first mouse event (for example mouse move). So the workaround I found is very simple - you just need to simulate mouse event with the same mouse position just before calling DoDragDrop:

void XYZControl_MouseDown(object sender, MouseEventArgs e)
{
    var senderControl = (Control) sender;
    ...
    Cursor.Position = senderControl.PointToScreen(new Point(e.X, e.Y));   // Workaround!
    if (DoDragDrop(senderControl, DragDropEffects.Move) == DragDropEffects.Move)
    {
    ...
    }
....
}

這篇關于來自另一個線程的 DoDragDrop()的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網！