how to get columns and column in matrix created in screenpainter

Hi,

I'm new in SAP B1 SDK. Here is my first question.

How can i get columns and column in a matrix created in screenpainter. Here is my code but line 3 will result to an error.

1. SAPbouiCOM.Form validationForm = (SAPbouiCOM.Form)SBO_Application.Forms.Item("Validation");

2. SAPbouiCOM.Columns columns;

3. columns = ((SAPbouiCOM.Matrix)validationForm.Items.Item("7")).Columns;