By default, the SelLenght property is -1 ( all text gets selected ). Use the SelLenght property to specify the number of characters being selected when the edit operations begins. The SelStart and SelLength properties have effect only if the control is editable. Use the AllowEdit property to allow control edits the data using a text box field. Use the Edit method to programmatically edit a cell using a textbox field. The SelLength property must be set in the code, before starting editing the cell. The control fires the BeforeCellEdit event when the control is about to open the text box editor. The control fires the AfterCellEdit property when the edit ends.