How to Setting Datagrid column formatting in code

private string setFormating(DataColumn bc)
{
string dataType = null;
switch(bc.DataType.ToString())
{
case "System.Int32":
dataType = "{0:#,###}";
break;
case "System.Decimal":
dataType = "{0:c}";
break;
case "System.DateTime":
dataType="{0:dd-mm-yyyy}";
break;
case "System.String":
dataType="";
break;
default:
dataType = "";
break;
}
return dataType;
}