Data Binding

The WebHierarchicalDataGrid™ control can bind to any supported hierarchical data source and display the data in a hierarchical grid view. Use the control’s DataSource or DataSourceID properties to set the data source. Set the DataKeyFields property to define the field which identifies unique records in the data source.

The WebHierarchicalDataGrid control automatically creates bands and columns when bound to data. The control walks the hierarchy creating ContainerGrid objects and binds them to each data island in the data source. The result is a hierarchical view in WebHierarchcialDataGrid using nested ContainerGrid objects. To control the generation of bands and columns, use the AutoGenerateBands and AutoGenerateColumns properties.

Supported Data Sources

WebHierarchicalDataGrid supports the following data sources:

Hierarchical Data Source Controls
- WebHierarchicalDataSource
- XmlDataSource
- SiteMapDataSource
DataSet
IEnumerable

DataSource/DataSourceID

At design time, set the DataSourceID Infragistics.web_{infragistics.web.ui.gridcontrols.webhierarchicaldatagrid}datasourceid.htmlproperty to the ID of the data source that you want to bind to. At runtime, you can either set the DataSource or the DataSourceID property to specify the data source. If you have load on demand enabled and getting data at runtime using the DataSource or DataSourceID property, you need to set the property on every postback. The reason is that the entire data source is not stored in ViewState and WebHierarchicalDataGrid needs the data source on every postback to know which level of data to bind to.

DataKeyFields

As mentioned, you can use the DataKeyFields property to specify one or more fields that uniquely identify the records in your data source. Multiple fields are comma separated. The DataKeyFields property exists for each band in the hierarchy.

This property is very important for proper functioning of WebHierarchicalDataGrid. You may not need it for simple data viewing; however, for data manipulations the property plays a vital role. When the DataKeyFields property has no value, a row object’s Index property is used to identify it. This is an unreliable way to identify a row since simple paging or sorting can change the index.

At design time, if you set a data source and enable Paging, Sorting, or Editing behaviors without setting the DataKeyFields property, the following message dialog displays: “For proper functioning of the WebHierarchicalDataGrid please specify the data key fields in the DataKeyFields property on all levels of the hierarchy: top level and the child bands”. At runtime, the following exception is thrown: “The DataKeyFields property must be set for the {0} band to perform the {1} operation”. Where {0} is the data member of the band and {1} is the name of the operation.

At design time, for certain data sources WebHierarchicalDataGrid will try to extract the information about data key fields from the data source and automatically apply the setting.

AutoGenerateBands

WebHierarchicalDataGrid exposes the AutoGenerateBands property to control displaying bands in the control. By default this property is set to True. This means that WebHierarchicalDataGrid generates all bands from the data source automatically. When binding at design time, the control creates the band definition in the markup and sets AutoGenerateBands to False.

To control band generation in WebHierarchicalDataGrid, set AutoGenerateBands to False and define your bands in the control.

AutoGenerateColumns

Similar to the AutoGenerateBands property, AutoGenerateColumns controls the generation of columns for each band in WebHierarchicalDataGrid. The property is provided by an object that implements the IBand property, hence every Band object as well as ContainerGrid object will have access to this property; however, the property setting does not propagate to child levels.

AutoGenerateColumns is True by default. When data binding at design time, WebHierarchicalDataGrid creates a column definition in the markup and sets this property to False. If set back to True, you will see duplicate columns when the control is rendered.

To control generating columns in each band, set a Band object’s AutoGenerateColumns property to False and define your column schema for that band.

The following code shows you how to define a band and column schema.

In HTML:

<%-- Set the AutoGenerateBands and AutoGenerateColumns properties to False --%>
<ig:WebHierarchicalDataGrid ID="WebHierarchicalDataGrid1" runat="server"
   AutoGenerateBands=" AutoGenerateColumns="
   DataMember="SqlDataSource1_DefaultView"
   DataSourceID="WebHierarchicalDataSource1" DefaultColumnWidth=""
   Key="SqlDataSource1_DefaultView" DataKeyFields="CategoryID">
   <%-- Define the Columns for the root band --%>
   <Columns>
      <ig:BoundDataField DataFieldName="CategoryName" Key="CategoryName">
         <Header Text="CategoryName" />
      </ig:BoundDataField>
      <ig:BoundDataField DataFieldName="Description" Key="Description">
         <Header Text="Description" />
      </ig:BoundDataField>
   </Columns>
   <%-- Define the child band and its column --%>
   <Bands>
      <ig:Band DataMember="SqlDataSource2_DefaultView" DefaultColumnWidth=""
               Height="" Key="SqlDataSource2_DefaultView" DataKeyFields="ProductID" Width="">
         <Columns>
            <ig:BoundDataField DataFieldName="ProductID" Key="ProductID">
               <Header Text="ProductID" />
            </ig:BoundDataField>
            <ig:BoundDataField DataFieldName="ProductName" Key="ProductName">
               <Header Text="ProductName" />
            </ig:BoundDataField>
            <ig:BoundDataField DataFieldName="QuantityPerUnit" Key="QuantityPerUnit">
               <Header Text="QuantityPerUnit" />
            </ig:BoundDataField>
            <ig:BoundDataField DataFieldName="UnitPrice" Key="UnitPrice">
               <Header Text="UnitPrice" />
            </ig:BoundDataField>
         </Columns>
      </ig:Band>
   </Bands>
</ig:WebHierarchicalDataGrid>

In Visual Basic:

' Define Columns
Dim boundField As New BoundDataField(True)
boundField.Key = "CategoryName"
boundField.Header.Text = "Category Name"
'Bind to CategoryName field in data source
boundField.DataFieldName = "CategoryName"
Me.WebHierarchicalDataGrid1.Columns.Add(boundField)
boundField = New BoundDataField(True)
boundField.Key = "Description"
boundField.Header.Text = "Description"
'Bind to Description field in data source
boundField.DataFieldName = "Description"
Me.WebHierarchicalDataGrid1.Columns.Add(boundField)
' Create band
Dim childBand As New Band()
childBand.DataKeyFields = "ProductID"
' Set the key from the data source
childBand.Key = "SqlDataSource2_DefaultView"
' Set the data member from the data source to bind to
childBand.DataMember = "SqlDataSource2_DefaultView"
Me.WebHierarchicalDataGrid1.Bands.Add(childBand)
' Define column for the child band
boundField = New BoundDataField(True)
boundField.Key = "ProductID"
boundField.Header.Text = "Product ID"
'Bind to Product ID field in data source
boundField.DataFieldName = "ProductID"
Me.WebHierarchicalDataGrid1.Bands("SqlDataSource2_DefaultView").Columns.Add(boundField)
' Define column for the child band
boundField = New BoundDataField(True)
boundField.Key = "ProductName"
boundField.Header.Text = "Product Name"
'Bind to Product Name field in data source
boundField.DataFieldName = "ProductName"
Me.WebHierarchicalDataGrid1.Bands("SqlDataSource2_DefaultView").Columns.Add(boundField)
' Define column for the child band
boundField = New BoundDataField(True)
boundField.Key = "QuantityPerUnit"
boundField.Header.Text = "Quantity Per Unit"
'Bind to QuantityPerUnit field in data source
boundField.DataFieldName = "QuantityPerUnit"
Me.WebHierarchicalDataGrid1.Bands("SqlDataSource2_DefaultView").Columns.Add(boundField)
' Define column for the child band
boundField = New BoundDataField(True)
boundField.Key = "UnitPrice"
boundField.Header.Text = "Unit Price"
'Bind to UnitPrice field in data source
boundField.DataFieldName = "UnitPrice"
Me.WebHierarchicalDataGrid1.Bands("SqlDataSource2_DefaultView").Columns.Add(boundField)

In C#:

// Define Columns
BoundDataField boundField = new BoundDataField(true);
boundField.Key = "CategoryName";
boundField.Header.Text = "Category Name";
//Bind to CategoryName field in data source
boundField.DataFieldName = "CategoryName";
this.WebHierarchicalDataGrid1.Columns.Add(boundField);
boundField = new BoundDataField(true);
boundField.Key = "Description";
boundField.Header.Text = "Description";
//Bind to Description field in data source
boundField.DataFieldName = "Description";
this.WebHierarchicalDataGrid1.Columns.Add(boundField);
// Create band
Band childBand = new Band();
childBand.DataKeyFields = "ProductID";
// Set the key from the data source
childBand.Key = "SqlDataSource2_DefaultView";
// Set the data member from the data source to bind to
childBand.DataMember = "SqlDataSource2_DefaultView";
this.WebHierarchicalDataGrid1.Bands.Add(childBand);
// Define column for the child band
boundField = new BoundDataField(true);
boundField.Key = "ProductID";
boundField.Header.Text = "Product ID";
// Bind to Product ID field in data source
boundField.DataFieldName = "ProductID";
this.WebHierarchicalDataGrid1.Bands["SqlDataSource2_DefaultView"].Columns.Add(boundField);
// Define column for the child band
boundField = new BoundDataField(true);
boundField.Key = "ProductName";
boundField.Header.Text = "Product Name";
// Bind to Product Name field in data source
boundField.DataFieldName = "ProductName";
this.WebHierarchicalDataGrid1.Bands["SqlDataSource2_DefaultView"].Columns.Add(boundField);
// Define column for the child band
boundField = new BoundDataField(true);
boundField.Key = "QuantityPerUnit";
boundField.Header.Text = "Quantity Per Unit";
//Bind to QuantityPerUnit field in data source
boundField.DataFieldName = "QuantityPerUnit";
this.WebHierarchicalDataGrid1.Bands["SqlDataSource2_DefaultView"].Columns.Add(boundField);
// Define column for the child band
boundField = new BoundDataField(true);
boundField.Key = "UnitPrice";
boundField.Header.Text = "Unit Price";
//Bind to UnitPrice field in data source
boundField.DataFieldName = "UnitPrice";
this.WebHierarchicalDataGrid1.Bands["SqlDataSource2_DefaultView"].Columns.Add(boundField);

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