Well I know this question has been asked a couple of times but none of the solutions worked for me. I simply want to pass a value from one form to a textbox in a different form.  

On the first form I have a data grid when double-clicked on it obtains a value from the datagrid column. 

```
public partial class AvailableRooms : Form
{   
   private void DCRoom(object sender, DataGridViewCellMouseEventArgs e) 
  {
   var roomnum = dgRooms.Rows[e.RowIndex].Cells["iRoomNum"].Value.ToString();
   RoomBooking rb = new RoomBooking();//The second form
   rb.roomnumber = roomnum;           
   rb.Show();        
 }
}

```

On the second form I have set the properties of the textbox 

```
public partial class RoomBooking : Form
{

   public RoomBooking()
    {
      StartPosition = FormStartPosition.CenterScreen;
      InitializeComponent();
  }

  public string roomnumber
   {
      get { return txtRoomNum.Text; }
      set {txtRoomNum.Text = value;}
    }

 }

```

Thanks in advance for the help?