將值從datetimepicker保存到SQL Server數據庫

Question

當我嘗試保存詳細信息時，我收到一條錯誤消息，內容如下。

在此處輸入圖片說明

如何將其轉換為字符串值？ 提前致謝！ 這是我的C＃代碼和錯誤消息。

private void button1_Click(object sender, EventArgs e)
{
    SqlConnection cn = new SqlConnection(@"Data Source=(LocalDB)\v11.0;AttachDbFilename=C:\Program Files\Microsoft SQL Server\MSSQL11.SQLEXPRESS\MSSQL\DATA\GCSCFC.mdf;Integrated Security=True;Connect Timeout=30");

    try
    {
        string sql = "INSERT INTO Leave (Employee_ID, Leave_Type,Leave_Date,Leave_Time_From, Leave_Time_To) values('" + txtEmpID.Text + "','" + cmbLeaveType.Text + "','" + PickerLeaveDate.Text + "','" + txtTimeFrom.Text + "','" + txtTimeTo.Text + "')";

        SqlCommand exesql = new SqlCommand(sql, cn);
        cn.Open();

        exesql.ExecuteNonQuery();

        MessageBox.Show("New Employee Added Successfully!", "Message", MessageBoxButtons.OK, MessageBoxIcon.Information);
    }
    catch (Exception ex)
    {
        MessageBox.Show(ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
    }
    finally
    {
        cn.Close();
    }
}

Answer 1

當數據庫列是DataTime之類的代碼時使用參數

        private void button1_Click(object sender, EventArgs e)
        {
            SqlConnection cn = new SqlConnection(@"Data Source=(LocalDB)\v11.0;AttachDbFilename=C:\Program Files\Microsoft SQL Server\MSSQL11.SQLEXPRESS\MSSQL\DATA\GCSCFC.mdf;Integrated Security=True;Connect Timeout=30");
            try
            {
                string sql = "INSERT INTO Leave (Employee_ID, Leave_Type,Leave_Date,Leave_Time_From, Leave_Time_To) values('" + @txtEmpID + "','" + @cmbLeaveType + "','" + @PickerLeaveDate + "','" + @txtTimeFrom + "','" + @txtTimeTo + "')";
                SqlCommand exesql = new SqlCommand(sql, cn);
                exesql.Parameters.Add("@txtEmpID", SqlDbType.VarChar);
                exesql.Parameters.Add("@cmbLeaveType", SqlDbType.VarChar);
                exesql.Parameters.Add("@PickerLeaveDate", SqlDbType.DateTime);
                exesql.Parameters.Add("@txtTimeFrom", SqlDbType.VarChar);
                exesql.Parameters.Add("@txtTimeTo", SqlDbType.VarChar);

                exesql.Parameters["@txtEmpID"].Value = txtEmpID.Text;
                exesql.Parameters["@cmbLeaveType"].Value = cmbLeaveType.Text;
                exesql.Parameters["@PickerLeaveDate"].Value = PickerLeaveDate.Value;
                exesql.Parameters["@txtTimeFrom"].Value = txtTimeFrom;
                exesql.Parameters["@txtTimeTo"].Value = txtTimeTo.Text;

                cn.Open();
                exesql.ExecuteNonQuery();
                MessageBox.Show("New Employee Added Successfully!", "Message", MessageBoxButtons.OK, MessageBoxIcon.Information);

            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
            }
            finally
            {
                cn.Close();
            }
        }
​