无法将文本从DataGridView拖放到TextBox C＃

Question

I have been using code that others online have supplied but for some reason it won't let me drag items from the datagridview to the textbox. I highlight a row in the dataGridView and try to drag it to the textbox but nothing happens. I have also enabled the drop property for the textBox but still no difference. Here's the code that I am using:

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

Here is a small sample that i have done to give you an idea on how to do this... works perfectly for me. I used WinForms here. If WPF, there may be some more events you will need to register to in order for the drag+drop to register...

Note that you will want to add more code here and there to perform what you really want to do when you drag an item from one control to the other.

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

can't you use DataGridViewCellMouseEventArgs e instead of hittest for getting row index in dataGridView1_CellMouseDown. below is your code modified hope this helps

  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;
    }