WebGrid.NET introduces a powerful feature that is able to perform aggregation function on grouped rows as well as all rows totalling. The provided aggregation functions such as Count, Sum, Average, Min and Max are generally applicable to most application's requirements.
During this walkthrough, you will learn how to do the following:
- Connect to a Microsoft Access database using Microsoft Jet 4.0 OLE DB Provider.
- Use Custom Aggregate function in WebGrid.
Prerequisites
In order to complete this walkthrough, you will need the following:
- Access to the Microsoft Access Northwind database.
- Visual Studio 2005/2008/2010 Application.
Step-By-Step Instructions
To create new web application and use custom aggregate function
- Bind WebGrid to AccessDataSource.
- Open WebGrid.NET Designer-Advanced-WebGrid-LayoutSettings and set the ColumnFooters to Yes.
- Group a column by "ReorderLevel" column by using GroupColumns.
- Set the AggregateFunction to "Custom" and FooterText to "Count =" to the UnitsOnOrder column.
- Add custom aggregate code into the WebGrid1_CustomAggregate server side event.
C# 
Copy Codeif (e.Column.DataMember == "UnitsOnOrder") { WebGridRowCollection rows = e.Rows; int count = 0; for (int i=0; i < rows.Count; i++) { WebGridCell cell = rows[i].Cells[e.Column.Position]; if (int.Parse( cell.Value.ToString() ) > 0) count++; } e.AggregateResult = count; }
- Compile and run the WebForm.