drag TreeView node to DataGridView cell problem

I have written this routine to drag a TreeView node-value to drop it on a DataGridView cell.

private void dataGridView1_DragDrop(object sender, DragEventArgs e)
        {
            if (e.Data.GetDataPresent(typeof(string)))
            {
                #region Find Row and Cell from Mouse Position
                Point grvScreenLocation = dataGridView1.PointToScreen(dataGridView1.Location);
                int tempX = DataGridView.MousePosition.X - grvScreenLocation.X + dataGridView1.Left;
                int tempY = DataGridView.MousePosition.Y - grvScreenLocation.Y + dataGridView1.Top;

                DataGridView.HitTestInfo hit = dataGridView1.HitTest(tempX, tempY);

                int cellX = hit.RowIndex;
                int cellY = hit.ColumnIndex;
                #endregion

                string droppedString = e.Data.GetData(typeof(string)) as string;

                DataGridViewRow selectedRow = dataGridView1.Rows[cellX];
                DataGridViewCell selectedCell = dataGridView1.Rows[cellX].Cells[cellY];

                if (!selectedRow.IsNewRow)
                {
                    selectedCell.Value = droppedString;
                    selectedCell.Tag = droppedString;
                    selectedCell.OwningRow.Cells[3].Value = colMappingType.Items[0];
                }
                else
                {                    
                    dataGridView1.Rows.Add();
                    dataGridView1.Rows[dataGridView1.Rows.Count-2].Cells[cellY].Value = droppedString;
                    dataGridView1.Rows[dataGridView1.Rows.Count-2].Cells[cellY].Tag = droppedString;
                    dataGridView1.Rows[dataGridView1.Rows.Count - 2].Cells[3].Value = colMappingType.Items[1];
                }
            }
        }

And I have written this routine to test whether the cells are actually been populated:

private void button1_Click(object sender, EventArgs e)
        {
            DataTable dataTable = new DataTable();
            dataTable.TableName = "Test";

            dataTable.Columns.Add("ColOne", typeof(bool));
            dataTable.Columns.Add("ColTwo", typeof(string));
            dataTable.Columns.Add("ColThr", typeof(string));
            dataTable.Columns.Add("ColFor");

            foreach (DataGridViewRow dgvRow in dataGridView1.Rows)
            {
                DataRow dataRow = dataTable.NewRow();

                int i=0;
                foreach (DataGridViewCell dgvCell in dgvRow.Cells)
                {
                    dataRow.ItemArray.SetValue(dgvCell.Value, i);
                    ++i;
                }

                dataTable.Rows.Add(dataRow);                
            }

            Form2 f = new Form2();
            f.DataGridView.DataSource = dataTable;
            f.Show();
        }
    }

the test code shows that the new DataGridView on Form2 has correct number of rows and columns. But contains no data.

What is actually happening?

How to solve this problem?

EDIT:

This code solved the problem.

private void button1_Click(object sender, EventArgs e)
        {
            DataTable dataTable = new DataTable();
            dataTable.TableName = "Test";

            dataTable.Columns.Add("ColOne", typeof(bool));
            dataTable.Columns.Add("ColTwo", typeof(string));
            dataTable.Columns.Add("ColThr", typeof(string));
            dataTable.Columns.Add("ColFor");

            foreach (DataGridViewRow dgvRow in dataGridView1.Rows)
            {
   开发者_开发百科             if (dgvRow.Cells[0].Value != null
                    && dgvRow.Cells[1].Value != null
                    && dgvRow.Cells[2].Value != null
                    && dgvRow.Cells[3].Value != null)
                {
                    DataRow dataRow = dataTable.NewRow();

                    dataRow[0] = dgvRow.Cells[0].Value;
                    dataRow[1] = dgvRow.Cells[1].Value;
                    dataRow[2] = dgvRow.Cells[2].Value;
                    dataRow[3] = dgvRow.Cells[3].Value;

                    dataTable.Rows.Add(dataRow);
                }
            }

            Form2 f = new Form2();
            f.DataGridView.DataSource = dataTable;
            f.Show();
        }

I am not even sure how to use ItemArray correctly, but the way you do it now doesn't work. Replace:

 dataRow.ItemArray.SetValue(dgvCell.Value, i);

with

dataRow[i] = dgvCell.Value;