无法将文本从 DataGridView 拖放到 TextBox C#

Question

我一直在使用其他人在线提供的代码，但由于某种原因，它不允许我将项目从 datagridview 拖动到文本框。我突出显示 dataGridView 中的一行并尝试将其拖到文本框，但没有任何反应。我还为 textBox 启用了 drop 属性，但仍然没有区别。这是我正在使用的代码：

private void dataGridView1_CellMouseDown(object sender, DataGridViewCellMouseEventArgs e)
    {
         if (e.Button == MouseButtons.Left)
         {
             DataGridView.HitTestInfo info = dataGridView1.HitTest(e.X, e.Y);
             if (info.RowIndex >= 0)
             {
                 if (info.RowIndex >= 0 && info.ColumnIndex >= 0)
                 {
                     string text = (String)
                      dataGridView1.Rows[info.RowIndex].Cells[info.ColumnIndex].Value;
                     if (text != null)
                         dataGridView1.DoDragDrop(text, DragDropEffects.Copy);
                 }
             }
         }
    }

    private void textBox1_DragDrop(object sender, DragEventArgs e)
    {
        if (e.Data.GetDataPresent(typeof(System.String)))
        {
            textBox1.Text = (System.String)e.Data.GetData(typeof(System.String));
        }
    }

    private void textBox1_DragEnter(object sender, DragEventArgs e)
    {
        e.Effect = DragDropEffects.Copy;
    }

Answer 1

这是我所做的一个小示例，旨在让您了解如何执行此操作……非常适合我。我在这里使用了 WinForms。如果是 WPF，您可能需要注册更多事件才能注册拖放操作...

请注意，当您将一个项目从一个控件拖到另一个控件时，您需要在各处添加更多代码来执行您真正想做的事情。

public partial class Form1 : Form
{
    private Rectangle dragBoxFromMouseDown;
    private int rowIndexFromMouseDown;
    private int rowIndexOfItemUnderMouseToDrop;
    private DataGridViewRow draggedrow;

    public Form1()
    {
        InitializeComponent();
    }

    private void Form1_Load(object sender, EventArgs e)
    {
        List<StringValue> Items = new List<StringValue>() { new StringValue("1"), new StringValue("2"), new StringValue("3"), new StringValue("4"), new StringValue("5"), new StringValue("6") };
        this.dataGridView1.DataSource = Items;

    }



    private void dataGridView1_MouseMove(object sender, MouseEventArgs e)
    {
        if ((e.Button & MouseButtons.Left) == MouseButtons.Left)
        {
            // If the mouse moves outside the rectangle, start the drag.
            if (dragBoxFromMouseDown != Rectangle.Empty &&
                !dragBoxFromMouseDown.Contains(e.X, e.Y))
            {

                // Proceed with the drag and drop, passing in the list item.                    
                DragDropEffects dropEffect = dataGridView1.DoDragDrop(
                dataGridView1.Rows[rowIndexFromMouseDown],
                DragDropEffects.Move);
            }
        }
    }

    private void dataGridView1_MouseDown(object sender, MouseEventArgs e)
    {
        // Get the index of the item the mouse is below.
        rowIndexFromMouseDown = dataGridView1.HitTest(e.X, e.Y).RowIndex;
        if (rowIndexFromMouseDown != -1)
        {
            // Remember the point where the mouse down occurred. 
            // The DragSize indicates the size that the mouse can move 
            // before a drag event should be started.                
            Size dragSize = SystemInformation.DragSize;

            // Create a rectangle using the DragSize, with the mouse position being
            // at the center of the rectangle.
            dragBoxFromMouseDown = new Rectangle(new Point(e.X - (dragSize.Width / 2),
                                                           e.Y - (dragSize.Height / 2)),
                                dragSize);
            this.draggedrow = this.dataGridView1.CurrentRow;
        }
        else
            // Reset the rectangle if the mouse is not over an item in the ListBox.
            dragBoxFromMouseDown = Rectangle.Empty;
    }

    private void dataGridView1_DragOver(object sender, DragEventArgs e)
    {
        e.Effect = DragDropEffects.Move;
    }

    private void textBox1_DragEnter(object sender, DragEventArgs e)
    {
        e.Effect = DragDropEffects.Move;
    }

    private void textBox1_DragDrop(object sender, DragEventArgs e)
    {
        this.textBox1.Text = (string)this.draggedrow.Cells["Value"].Value;
    }


}

public class StringValue
{
    public StringValue(string s)
    {
        _value = s;
    }
    public string Value { get { return _value; } set { _value = value; } }
    string _value;
}

Answer 2

你不能使用 DataGridViewCellMouseEventArgs e 而不是 hittest 来获取 dataGridView1_CellMouseDown 中的行索引。以下是您修改过的代码，希望对您有所帮助

  private void dataGridView1_CellMouseDown(object sender, DataGridViewCellMouseEventArgs e)
    {
        if (e.Button == MouseButtons.Left)
        {


            if (e.RowIndex >= 0)
            {
                if (e.RowIndex >= 0 && e.ColumnIndex >= 0)
                {
                    string text = (String)
                     dataGridView1.Rows[e.RowIndex].Cells[e.ColumnIndex].Value;
                    if (text != null)
                        dataGridView1.DoDragDrop(text, DragDropEffects.Copy);
                }
            }  

        }
    }

    private void textBox1_DragDrop(object sender, DragEventArgs e)
    {
        if (e.Data.GetDataPresent(typeof(System.String)))
        {
            textBox1.Text = (System.String)e.Data.GetData(typeof(System.String));
        }
    }

    private void textBox1_DragEnter(object sender, DragEventArgs e)
    {
        e.Effect = DragDropEffects.Copy;
    }