how to get selected row values of datagridview in textboxes

Try This
TextBox.Text = GridView.SelectedRow.Cells[3].Text;
Instead Cells[3] you can select the required cell value to the textbox

The CellContentClick works for subsequent selections, but does not fill the text boxes for when the datagridview is first displayed. However, you can use a separate method to fill the textboxes, passing in the e.RowIndex. After the datagridview has been displayed, call the method with the row value of the initial 'record'.

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            dgvExceptions.DataSource = ds.Tables[0];<br />
2.            dgvExceptions.Columns[0].HeaderText = "ID";<br />
3.            dgvExceptions.Columns[0].Width = 30;<br />
4.            dgvExceptions.Columns[0].DefaultCellStyle.Alignment =<br />
5.                DataGridViewContentAlignment.MiddleRight;<br />
6.            dgvExceptions.Columns[1].Visible = false;<br />
7.            dgvExceptions.Columns[2].HeaderText = "Occurred On";<br />
8.            dgvExceptions.Columns[2].Width = 70;<br />
9.            dgvExceptions.Sort(dgvExceptions.Columns[2], ListSortDirection.Descending);<br />
10.            dgvExceptions.Columns[3].Visible = false;<br />
11.            dgvExceptions.Columns[4].Visible = false;<br />
12.            dgvExceptions.Columns[5].Visible = false;<br />
13.            dgvExceptions.Columns[6].Visible = false;<br />
14.            dgvExceptions.Columns[7].Width = 317;<br />
15.            dgvExceptions.Columns[8].Visible = false;<br />
16.            dgvExceptions.Rows[0].Selected = true;<br />
17.            SetUpDataGridView(0);<br />
18.<br />
19.<br />
20.        private void dgvExceptions_CellContentClick(object sender, DataGridViewCellEventArgs e)<br />
21.        {<br />
22.            SetUpDataGridView(e.RowIndex);<br />
23.        }<br />
24.<br />
25.        private void SetUpDataGridView(int p)<br />
26.        {<br />
27.            DataGridViewRow row = dgvExceptions.Rows[p];<br />
28.            txtExceptionId.Text = row.Cells[0].Value.ToString();<br />
29.            txtConnection.Text = row.Cells[1].Value.ToString();<br />
30.            txtExceptionType.Text = row.Cells[6].Value.ToString();<br />
31.            txtDateOccurred.Text = row.Cells[2].Value.ToString();<br />
32.            txtClass.Text = row.Cells[3].Value.ToString();<br />
33.            txtModule.Text = row.Cells[4].Value.ToString();<br />
34.            txtMethod.Text = row.Cells[5].Value.ToString();<br />
35.            txtMessage.Text = row.Cells[7].Value.ToString();<br />
36.        }<br />