Alan,

>We have data displayed in a MmDataGridView. The user will update several rows and then push a save button. We can loop through the dataset, set an entity to each row, and fire the rules for each entity.
>
>However, if a rule fails, the error icon always shows up next to the currently selected cell. How do we set the icon to the cell in error?

In your business rule's CheckRulesHook() method do you have code that sets the CurrentRow property? This tells the Windows Forms error provider which row the error belongs to. For example:

public override bool CheckRulesHook(DataSet ds, string tableName)
{
	if (ds.Tables[tableName].Rows.Count > 0)
	{
		this.CurrentRow = 0;
		foreach (DataRow Row in ds.Tables[tableName].Rows)
		{
			if (Row.RowState != DataRowState.Unchanged && Row.RowState != DataRowState.Deleted)
			{
				OrderDetailEntity Entity = new OrderDetailEntity();
				Entity.SetDataRow(Row);

				// Call validation methods
				this.ValidateDiscount(Entity.Discount);
				this.ValidateOrderID(Entity.OrderID);
				this.ValidateProductID(Entity.ProductID);
				this.ValidateQuantity(Entity.Quantity);
				this.ValidateUnitPrice(Entity.UnitPrice);
			}
			this.CurrentRow++;
		}

	}

	// Change this return value to indicate result of rule checking
	return this.ErrorProviderBrokenRuleCount == 0;
}

Best Regards,