5.16 How can I do cell by cell validation in a datagrid?
There are problems trying to implement cell by cell validation using the grid's Validating event architecture. The problem is that the grid is not the object handling the data. Instead, a TextBox or some other control is the control managing the changing of the cell contents. One way to implement the validation at the grid level is to handle the CurrentCellChanged event, and if the previous cell's value is not proper, then return to that cell. You can download a sample that implements this process. The sample only handles the validation from cell to cell movement. If you want to handle the validation when the user clicks on the forms Close button, then you would have to add a special event handler for this and do one last validation at this point.
5.12 How can I restrict the keystrokes that will be accepted in a column of my datagrid?
You can create a custom column style and handle the KeyPress event of its TextBox member. Below is the code showing how this might be done. You can also download a sample project (C#, VB) that shows an implementation of this idea.
public class DataGridDigitsTextBoxColumn : DataGridTextBoxColumn
{
public DataGridDigitsTextBoxColumn(System.ComponentModel.PropertyDescriptor pd, string format, bool b)
: base(pd, format, b)
{
this.TextBox.KeyPress += new System.Windows.Forms.KeyPressEventHandler(HandleKeyPress);