Datetime picker in Datagridview

Question

I want to display a time(only HH:mm) in a column of datagridview.Below is the code which tried .The type for column is DataGridViewTextBoxColumn

 

Adding row to grid using below code

private void btnAdd_Click(object sender, EventArgs e)
{
dgvDatetime.Rows.Add(1);
}
private void dgvDatetime_CellClick(object sender, DataGridViewCellEventArgs e)
{
if (e.ColumnIndex == 0)
{
//Initialized a new DateTimePicker Control
oDateTimePicker = new DateTimePicker();
//Adding DateTimePicker control into DataGridView
dgvDatetime.Controls.Add(oDateTimePicker);
// Setting the format (i.e. 2014-10-10)
oDateTimePicker.Format = DateTimePickerFormat.Custom;
oDateTimePicker.CustomFormat = "HH:mm";
oDateTimePicker.ShowUpDown = true;
// It returns the retangular area that represents the Display area for a cell
Rectangle oRectangle = dgvDatetime.GetCellDisplayRectangle(e.ColumnIndex, e.RowIndex, true);
//Setting area for DateTimePicker Control
oDateTimePicker.Size = new Size(oRectangle.Width, oRectangle.Height);
// Setting Location
oDateTimePicker.Location = new Point(oRectangle.X, oRectangle.Y);
// An event attached to dateTimePicker Control which is fired when DateTimeControl is closed
oDateTimePicker.CloseUp += new EventHandler(oDateTimePicker_CloseUp);
// An event attached to dateTimePicker Control which is fired when any date is selected
oDateTimePicker.TextChanged += new EventHandler(dateTimePicker_OnTextChange);
// Now make it visible
oDateTimePicker.Visible = true;
}
}
private void dateTimePicker_OnTextChange(object sender, EventArgs e)
{
// Saving the 'Selected Date on Calendar' into DataGridView current cell
dgvDatetime.CurrentCell.Value = oDateTimePicker.Text.ToString();
}
void oDateTimePicker_CloseUp(object sender, EventArgs e)
{
// Hiding the control after use
oDateTimePicker.Visible = false;
}
By adding a button i am testing the value as below
private void btnget_Click(object sender, EventArgs e)
{
try
{
string _fromtime = dgvDatetime.Rows[0].Cells["ColFromTime"].Value.ToString();
}
catch (Exception ex)
{
ex.ToString();
// throw;
}
}

By the above code i get the time only when i click in the cell and when i want to read the cell value it returns null.If and only if i click in the cell and edit the datetimepicker i can read the value of the cell.But i want to get the time in cell on adding the row to datagrid and get the value of the cell even if i dont edit the datetimepicker