C# 拖放技術的典型應用

WinForms 拖放基礎實現：TextBox 間文字拖放完整步驟

開發步驟

1. 新增表單，放置兩個 Label、兩個 TextBox (txtDataTarget、txtSource)
2. 設定 txtDataTarget.AllowDrop = true
3. 實現三個核心事件

核心代碼

private void txtDataTarget_DragDrop(object sender, DragEventArgs e) {
    txtDataTarget.Text = e.Data.GetData(DataFormats.Text).ToString();
}

private void txtDataTarget_DragEnter(object sender, DragEventArgs e) {
    e.Effect = DragDropEffects.Copy; // 顯示複製圖標
}

private void txtSource_MouseMove(object sender, MouseEventArgs e) {
    if ((e.Button & MouseButtons.Left) == MouseButtons.Left) {
        string reportPath = Application.StartupPath.Substring(0, 
            Application.StartupPath.Substring(0, Application.StartupPath.LastIndexOf("\\")).LastIndexOf("\\"));
        reportPath += @"\sl3293dwarro.cur";
        Cursor MyNoDropCursor = new Cursor(reportPath);
        DragDropEffects dropEffect = this.txtSource.DoDragDrop(this.txtSource.Text, 
            DragDropEffects.Copy | DragDropEffects.Link);
    }
}

關鍵點：

• AllowDrop 啟用放置目標
• DragEnter 設定 e.Effect 回饋視覺提示
• DoDragDrop 發起拖放，指定資料與允許效果
• 自訂游標載入路徑處理