Grid View for ASP.NET Web Forms - How to implement the master-detail functionality with list data sources

This example demonstrates how to create List data sources and bind master and detail grids to those data sources.

Overview

Create a List data source for a master grid with an ID field. Then create a List data source for detail grids. The detail data source contains two fields: ID and ParentID. The ParentID field corresponds to the master data source's ID field.

public static List<Parent> CreateMasterData(int masterRowCount) {
    List<Parent> parentList = new List<Parent>();
    for (int i = 0; i < masterRowCount; i++) {
        parentList.Add(new Parent() {
            ID = i,
            Name = "Parent" + i.ToString()
        });
    }
    return parentList;
}

public static List<Child> CreateChildData(int childRowCount, int maxMasterIndex) {
    List<Child> childList = new List<Child>();
    Random r = new Random();
    for (int i = 0; i < childRowCount; i++) {
        childList.Add(new Child() {
            ID = i,
            Name = "Child" + i.ToString(),
            ParentID = r.Next(maxMasterIndex)
        });
    }
    return childList;
}

In the page's Init handler, bind the master grid to its data source. In the detail grid's server-side BeforePerformDataSelect event handler, get the master row's key value (the master data source's ID field) and filter detail data based on this value (the detail data source's ParentID field). Bind the detail grid to the filtered detail data source.

protected void Page_Init(object sender, EventArgs e) {
    masterGrid.DataSource = ParentData;
    masterGrid.DataBind();
}

protected void detailGrid_BeforePerformDataSelect(object sender, EventArgs e) {
    ASPxGridView detailGrid = (ASPxGridView)sender;
    int id = (int)detailGrid.GetMasterRowKeyValue();
    var result = from q in ChildData
                    where q.ParentID == id
                    select q;
    detailGrid.DataSource = result;
}

Files to Review

• Data.cs (VB: Data.vb)
• Default.aspx (VB: Default.aspx)
• Default.aspx.cs (VB: Default.aspx.vb)

Documentation

• Master-Detail Relationship

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