Export (0) Print
Expand All

HierarchicalDataBoundControl Class

Serves as the base class for all ASP.NET version 2.0 data-bound controls that display their data in hierarchical form.

Namespace:  System.Web.UI.WebControls
Assembly:  System.Web (in System.Web.dll)

public abstract class HierarchicalDataBoundControl : BaseDataBoundControl
<asp:HierarchicalDataBoundControl />

The HierarchicalDataBoundControl type exposes the following members.

  NameDescription
Protected methodHierarchicalDataBoundControlInitializes a new instance of the HierarchicalDataBoundControl class.
Top

  NameDescription
Public propertyAccessKeyGets or sets the access key that allows you to quickly navigate to the Web server control. (Inherited from WebControl.)
Protected propertyAdapterGets the browser-specific adapter for the control. (Inherited from Control.)
Public propertyAppRelativeTemplateSourceDirectoryGets or sets the application-relative virtual directory of the Page or UserControl object that contains this control. (Inherited from Control.)
Public propertyAttributesGets the collection of arbitrary attributes (for rendering only) that do not correspond to properties on the control. (Inherited from WebControl.)
Public propertyBackColorGets or sets the background color of the Web server control. (Inherited from WebControl.)
Public propertyBindingContainerInfrastructure. Gets the control that contains this control's data binding. (Inherited from Control.)
Public propertyBorderColorGets or sets the border color of the Web control. (Inherited from WebControl.)
Public propertyBorderStyleGets or sets the border style of the Web server control. (Inherited from WebControl.)
Public propertyBorderWidthGets or sets the border width of the Web server control. (Inherited from WebControl.)
Protected propertyChildControlsCreatedGets a value that indicates whether the server control's child controls have been created. (Inherited from Control.)
Public propertyClientIDGets the control ID for HTML markup that is generated by ASP.NET. (Inherited from Control.)
Public propertyClientIDModeGets or sets the algorithm that is used to generate the value of the ClientID property. (Inherited from Control.)
Protected propertyClientIDSeparatorGets a character value representing the separator character used in the ClientID property. (Inherited from Control.)
Protected propertyContextGets the HttpContext object associated with the server control for the current Web request. (Inherited from Control.)
Public propertyControlsGets a ControlCollection object that represents the child controls for a specified server control in the UI hierarchy. (Inherited from Control.)
Public propertyControlStyleGets the style of the Web server control. This property is used primarily by control developers. (Inherited from WebControl.)
Public propertyControlStyleCreatedGets a value indicating whether a Style object has been created for the ControlStyle property. This property is primarily used by control developers. (Inherited from WebControl.)
Public propertyCssClassGets or sets the Cascading Style Sheet (CSS) class rendered by the Web server control on the client. (Inherited from WebControl.)
Public propertyDataItemContainerGets a reference to the naming container if the naming container implements IDataItemContainer. (Inherited from Control.)
Public propertyDataKeysContainerGets a reference to the naming container if the naming container implements IDataKeysControl. (Inherited from Control.)
Public propertyDataSourceGets or sets the object from which the data-bound control retrieves its list of data items. (Inherited from BaseDataBoundControl.)
Public propertyDataSourceIDGets or sets the ID of the control from which the data-bound control retrieves its list of data items. (Overrides BaseDataBoundControl.DataSourceID.)
Protected propertyDesignModeGets a value indicating whether a control is being used on a design surface. (Inherited from Control.)
Public propertyEnabledGets or sets a value indicating whether the Web server control is enabled. (Inherited from WebControl.)
Public propertyEnableThemingGets or sets a value indicating whether themes apply to this control. (Inherited from WebControl.)
Public propertyEnableViewStateGets or sets a value indicating whether the server control persists its view state, and the view state of any child controls it contains, to the requesting client. (Inherited from Control.)
Protected propertyEventsGets a list of event handler delegates for the control. This property is read-only. (Inherited from Control.)
Public propertyFontGets the font properties associated with the Web server control. (Inherited from WebControl.)
Public propertyForeColorGets or sets the foreground color (typically the color of the text) of the Web server control. (Inherited from WebControl.)
Public propertyHasAttributesGets a value indicating whether the control has attributes set. (Inherited from WebControl.)
Protected propertyHasChildViewStateGets a value indicating whether the current server control's child controls have any saved view-state settings. (Inherited from Control.)
Public propertyHeightGets or sets the height of the Web server control. (Inherited from WebControl.)
Public propertyIDGets or sets the programmatic identifier assigned to the server control. (Inherited from Control.)
Protected propertyIdSeparatorInfrastructure. Gets the character used to separate control identifiers. (Inherited from Control.)
Protected propertyInitializedGets a value indicating whether the data-bound control has been initialized. (Inherited from BaseDataBoundControl.)
Protected propertyIsBoundUsingDataSourceIDGets a value indicating whether the DataSourceID property is set. (Inherited from BaseDataBoundControl.)
Protected propertyIsChildControlStateClearedGets a value indicating whether controls contained within this control have control state. (Inherited from Control.)
Protected propertyIsDataBindingAutomaticGets a value that indicates whether data binding is automatic. (Inherited from BaseDataBoundControl.)
Protected propertyIsEnabledGets a value indicating whether the control is enabled. (Inherited from WebControl.)
Protected propertyIsTrackingViewStateGets a value that indicates whether the server control is saving changes to its view state. (Inherited from Control.)
Protected propertyIsUsingModelBindersWhen implemented in a derived class, gets a value that indicates whether the control is using model binders. (Inherited from BaseDataBoundControl.)
Protected propertyIsViewStateEnabledGets a value indicating whether view state is enabled for this control. (Inherited from Control.)
Protected propertyLoadViewStateByIDGets a value indicating whether the control participates in loading its view state by ID instead of index. (Inherited from Control.)
Public propertyNamingContainerGets a reference to the server control's naming container, which creates a unique namespace for differentiating between server controls with the same Control.ID property value. (Inherited from Control.)
Public propertyPageGets a reference to the Page instance that contains the server control. (Inherited from Control.)
Public propertyParentGets a reference to the server control's parent control in the page control hierarchy. (Inherited from Control.)
Public propertyRenderingCompatibilityGets a value that specifies the ASP.NET version that rendered HTML will be compatible with. (Inherited from Control.)
Protected propertyRequiresDataBindingGets or sets a value indicating whether the DataBind method should be called. (Inherited from BaseDataBoundControl.)
Public propertySiteGets information about the container that hosts the current control when rendered on a design surface. (Inherited from Control.)
Public propertySkinIDGets or sets the skin to apply to the control. (Inherited from WebControl.)
Public propertyStyleGets a collection of text attributes that will be rendered as a style attribute on the outer tag of the Web server control. (Inherited from WebControl.)
Public propertySupportsDisabledAttributeGets a value that indicates whether the control should set the disabled attribute of the rendered HTML element to "disabled" when the control's IsEnabled property is false. (Inherited from BaseDataBoundControl.)
Public propertyTabIndexGets or sets the tab index of the Web server control. (Inherited from WebControl.)
Protected propertyTagKeyGets the HtmlTextWriterTag value that corresponds to this Web server control. This property is used primarily by control developers. (Inherited from WebControl.)
Protected propertyTagNameGets the name of the control tag. This property is used primarily by control developers. (Inherited from WebControl.)
Public propertyTemplateControlGets or sets a reference to the template that contains this control. (Inherited from Control.)
Public propertyTemplateSourceDirectoryGets the virtual directory of the Page or UserControl that contains the current server control. (Inherited from Control.)
Public propertyToolTipGets or sets the text displayed when the mouse pointer hovers over the Web server control. (Inherited from WebControl.)
Public propertyUniqueIDGets the unique, hierarchically qualified identifier for the server control. (Inherited from Control.)
Public propertyValidateRequestModeGets or sets a value that indicates whether the control checks client input from the browser for potentially dangerous values. (Inherited from Control.)
Protected propertyViewStateGets a dictionary of state information that allows you to save and restore the view state of a server control across multiple requests for the same page. (Inherited from Control.)
Protected propertyViewStateIgnoresCaseGets a value that indicates whether the StateBag object is case-insensitive. (Inherited from Control.)
Public propertyViewStateModeGets or sets the view-state mode of this control. (Inherited from Control.)
Public propertyVisibleGets or sets a value that indicates whether a server control is rendered as UI on the page. (Inherited from Control.)
Public propertyWidthGets or sets the width of the Web server control. (Inherited from WebControl.)
Top

  NameDescription
Protected methodAddAttributesToRenderAdds HTML attributes and styles that need to be rendered to the specified HtmlTextWriterTag. This method is used primarily by control developers. (Inherited from WebControl.)
Protected methodAddedControlCalled after a child control is added to the Controls collection of the Control object. (Inherited from Control.)
Protected methodAddParsedSubObjectNotifies the server control that an element, either XML or HTML, was parsed, and adds the element to the server control's ControlCollection object. (Inherited from Control.)
Public methodApplyStyleCopies any nonblank elements of the specified style to the Web control, overwriting any existing style elements of the control. This method is primarily used by control developers. (Inherited from WebControl.)
Public methodApplyStyleSheetSkinApplies the style properties defined in the page style sheet to the control. (Inherited from Control.)
Protected methodBeginRenderTracingBegins design-time tracing of rendering data. (Inherited from Control.)
Protected methodBuildProfileTreeInfrastructure. Gathers information about the server control and delivers it to the Trace property to be displayed when tracing is enabled for the page. (Inherited from Control.)
Protected methodClearCachedClientIDInfrastructure. Sets the cached ClientID value to null. (Inherited from Control.)
Protected methodClearChildControlStateDeletes the control-state information for the server control's child controls. (Inherited from Control.)
Protected methodClearChildStateDeletes the view-state and control-state information for all the server control's child controls. (Inherited from Control.)
Protected methodClearChildViewStateDeletes the view-state information for all the server control's child controls. (Inherited from Control.)
Protected methodClearEffectiveClientIDModeInfrastructure. Sets the ClientIDMode property of the current control instance and of any child controls to Inherit. (Inherited from Control.)
Protected methodConfirmInitStateSets the initialized state of the data-bound control. (Inherited from BaseDataBoundControl.)
Public methodCopyBaseAttributesCopies the properties not encapsulated by the Style object from the specified Web server control to the Web server control that this method is called from. This method is used primarily by control developers. (Inherited from WebControl.)
Protected methodCreateChildControlsCalled by the ASP.NET page framework to notify server controls that use composition-based implementation to create any child controls they contain in preparation for posting back or rendering. (Inherited from Control.)
Protected methodCreateControlCollectionCreates a new ControlCollection object to hold the child controls (both literal and server) of the server control. (Inherited from Control.)
Protected methodCreateControlStyleCreates the style object that is used internally by the WebControl class to implement all style related properties. This method is used primarily by control developers. (Inherited from WebControl.)
Public methodDataBind()Binds a data source to the invoked server control and all its child controls. (Inherited from BaseDataBoundControl.)
Protected methodDataBind(Boolean)Binds a data source to the invoked server control and all its child controls with an option to raise the DataBinding event. (Inherited from Control.)
Protected methodDataBindChildrenBinds a data source to the server control's child controls. (Inherited from Control.)
Public methodDisposeEnables a server control to perform final clean up before it is released from memory. (Inherited from Control.)
Protected methodEndRenderTracingEnds design-time tracing of rendering data. (Inherited from Control.)
Protected methodEnsureChildControlsDetermines whether the server control contains child controls. If it does not, it creates child controls. (Inherited from Control.)
Protected methodEnsureDataBoundCalls the DataBind method if the DataSourceID property is set and the data-bound control is marked to require binding. (Inherited from BaseDataBoundControl.)
Protected methodEnsureIDCreates an identifier for controls that do not have an identifier assigned. (Inherited from Control.)
Public methodEquals(Object)Determines whether the specified object is equal to the current object. (Inherited from Object.)
Protected methodFinalizeAllows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
Public methodFindControl(String)Searches the current naming container for a server control with the specified id parameter. (Inherited from Control.)
Protected methodFindControl(String, Int32)Infrastructure. Searches the current naming container for a server control with the specified id and an integer, specified in the pathOffset parameter, which aids in the search. You should not override this version of the FindControl method. (Inherited from Control.)
Public methodFocusSets input focus to a control. (Inherited from Control.)
Protected methodGetDataRetrieves a HierarchicalDataSourceView object that the data-bound control uses to perform data operations.
Protected methodGetDataSourceRetrieves the IHierarchicalDataSource that the data-bound control is associated with, if any.
Protected methodGetDesignModeStateInfrastructure. Gets design-time data for a control. (Inherited from Control.)
Public methodGetHashCodeServes as the default hash function. (Inherited from Object.)
Public methodGetRouteUrl(Object)Gets the URL that corresponds to a set of route parameters. (Inherited from Control.)
Public methodGetRouteUrl(RouteValueDictionary)Gets the URL that corresponds to a set of route parameters. (Inherited from Control.)
Public methodGetRouteUrl(String, Object)Gets the URL that corresponds to a set of route parameters and a route name. (Inherited from Control.)
Public methodGetRouteUrl(String, RouteValueDictionary)Gets the URL that corresponds to a set of route parameters and a route name. (Inherited from Control.)
Public methodGetTypeGets the Type of the current instance. (Inherited from Object.)
Public methodGetUniqueIDRelativeToReturns the prefixed portion of the UniqueID property of the specified control. (Inherited from Control.)
Public methodHasControlsDetermines if the server control contains any child controls. (Inherited from Control.)
Protected methodHasEventsReturns a value indicating whether events are registered for the control or any child controls. (Inherited from Control.)
Protected methodIsLiteralContentInfrastructure. Determines if the server control holds only literal content. (Inherited from Control.)
Protected methodLoadControlStateRestores control-state information from a previous page request that was saved by the SaveControlState method. (Inherited from Control.)
Protected methodLoadViewStateRestores view-state information from a previous request that was saved with the SaveViewState method. (Inherited from WebControl.)
Protected methodMapPathSecureRetrieves the physical path that a virtual path, either absolute or relative, maps to. (Inherited from Control.)
Protected methodMarkAsDataBoundSets the state of the control in view state as successfully bound to data.
Protected methodMemberwiseCloneCreates a shallow copy of the current Object. (Inherited from Object.)
Public methodMergeStyleCopies any nonblank elements of the specified style to the Web control, but will not overwrite any existing style elements of the control. This method is used primarily by control developers. (Inherited from WebControl.)
Protected methodOnBubbleEventDetermines whether the event for the server control is passed up the page's UI server control hierarchy. (Inherited from Control.)
Protected methodOnDataBindingRaises the DataBinding event. (Inherited from Control.)
Protected methodOnDataBoundRaises the DataBound event. (Inherited from BaseDataBoundControl.)
Protected methodOnDataPropertyChangedCalled when one of the base data source identification properties is changed, to re-bind the data-bound control to its data. (Overrides BaseDataBoundControl.OnDataPropertyChanged().)
Protected methodOnDataSourceChangedCalled when the IHierarchicalDataSource instance that the data-bound control works with raises the DataSourceChanged event.
Protected methodOnInitHandles the Init event. (Inherited from BaseDataBoundControl.)
Protected methodOnLoadHandles the Load event. (Overrides Control.OnLoad(EventArgs).)
Protected methodOnPagePreLoadSets the initialized state of the data-bound control before the control is loaded. (Overrides BaseDataBoundControl.OnPagePreLoad(Object, EventArgs).)
Protected methodOnPreRenderHandles the PreRender event. (Inherited from BaseDataBoundControl.)
Protected methodOnUnloadRaises the Unload event. (Inherited from Control.)
Protected methodOpenFileGets a Stream used to read a file. (Inherited from Control.)
Protected methodPerformDataBindingWhen overridden in a derived class, binds data from the data source to the control.
Protected methodPerformSelectRetrieves data from the associated data source. (Overrides BaseDataBoundControl.PerformSelect().)
Protected methodRaiseBubbleEventAssigns any sources of the event and its information to the control's parent. (Inherited from Control.)
Protected methodRemovedControlCalled after a child control is removed from the Controls collection of the Control object. (Inherited from Control.)
Protected methodRenderRenders the control to the specified HTML writer. (Inherited from WebControl.)
Public methodRenderBeginTagRenders the HTML opening tag of the control to the specified writer. This method is used primarily by control developers. (Inherited from WebControl.)
Protected methodRenderChildrenOutputs the content of a server control's children to a provided HtmlTextWriter object, which writes the content to be rendered on the client. (Inherited from Control.)
Protected methodRenderContentsRenders the contents of the control to the specified writer. This method is used primarily by control developers. (Inherited from WebControl.)
Public methodRenderControl(HtmlTextWriter)Outputs server control content to a provided HtmlTextWriter object and stores tracing information about the control if tracing is enabled. (Inherited from Control.)
Protected methodRenderControl(HtmlTextWriter, ControlAdapter)Outputs server control content to a provided HtmlTextWriter object using a provided ControlAdapter object. (Inherited from Control.)
Public methodRenderEndTagRenders the HTML closing tag of the control into the specified writer. This method is used primarily by control developers. (Inherited from WebControl.)
Protected methodResolveAdapterGets the control adapter responsible for rendering the specified control. (Inherited from Control.)
Public methodResolveClientUrlGets a URL that can be used by the browser. (Inherited from Control.)
Public methodResolveUrlConverts a URL into one that is usable on the requesting client. (Inherited from Control.)
Protected methodSaveControlStateSaves any server control state changes that have occurred since the time the page was posted back to the server. (Inherited from Control.)
Protected methodSaveViewStateSaves any state that was modified after the TrackViewState method was invoked. (Inherited from WebControl.)
Protected methodSetDesignModeStateSets design-time data for a control. (Inherited from Control.)
Public methodSetRenderMethodDelegateInfrastructure. Assigns an event handler delegate to render the server control and its content into its parent control. (Inherited from Control.)
Public methodSetTraceData(Object, Object)Sets trace data for design-time tracing of rendering data, using the trace data key and the trace data value. (Inherited from Control.)
Public methodSetTraceData(Object, Object, Object)Sets trace data for design-time tracing of rendering data, using the traced object, the trace data key, and the trace data value. (Inherited from Control.)
Public methodToStringReturns a string that represents the current object. (Inherited from Object.)
Protected methodTrackViewStateCauses the control to track changes to its view state so they can be stored in the object's ViewState property. (Inherited from WebControl.)
Protected methodValidateDataSourceVerifies that the object a data-bound control binds to is one it can work with. (Overrides BaseDataBoundControl.ValidateDataSource(Object).)
Top

  NameDescription
Public eventDataBindingOccurs when the server control binds to a data source. (Inherited from Control.)
Public eventDataBoundOccurs after the server control binds to a data source. (Inherited from BaseDataBoundControl.)
Public eventDisposedOccurs when a server control is released from memory, which is the last stage of the server control lifecycle when an ASP.NET page is requested. (Inherited from Control.)
Public eventInitOccurs when the server control is initialized, which is the first step in its lifecycle. (Inherited from Control.)
Public eventLoadOccurs when the server control is loaded into the Page object. (Inherited from Control.)
Public eventPreRenderOccurs after the Control object is loaded but prior to rendering. (Inherited from Control.)
Public eventUnloadOccurs when the server control is unloaded from memory. (Inherited from Control.)
Top

  NameDescription
Public Extension MethodEnablePersistedSelectionEnables selection to be persisted in data controls that support selection and paging. (Defined by DynamicDataExtensions.)
Public Extension MethodFindDataSourceControlReturns the data source that is associated with the data control for the specified control. (Defined by DynamicDataExtensions.)
Public Extension MethodFindFieldTemplateReturns the field template for the specified column in the specified control's naming container. (Defined by DynamicDataExtensions.)
Public Extension MethodFindMetaTableReturns the metatable object for the containing data control. (Defined by DynamicDataExtensions.)
Top

  NameDescription
Explicit interface implemetationPrivate methodIAttributeAccessor.GetAttributeInfrastructure. Gets an attribute of the Web control with the specified name. (Inherited from WebControl.)
Explicit interface implemetationPrivate methodIAttributeAccessor.SetAttributeSets an attribute of the Web control to the specified name and value. (Inherited from WebControl.)
Explicit interface implemetationPrivate propertyIControlBuilderAccessor.ControlBuilderFor a description of this member, see IControlBuilderAccessor.ControlBuilder. (Inherited from Control.)
Explicit interface implemetationPrivate methodIControlDesignerAccessor.GetDesignModeStateFor a description of this member, see IControlDesignerAccessor.GetDesignModeState. (Inherited from Control.)
Explicit interface implemetationPrivate methodIControlDesignerAccessor.SetDesignModeStateFor a description of this member, see IControlDesignerAccessor.SetDesignModeState. (Inherited from Control.)
Explicit interface implemetationPrivate methodIControlDesignerAccessor.SetOwnerControlInfrastructure. For a description of this member, see IControlDesignerAccessor.SetOwnerControl. (Inherited from Control.)
Explicit interface implemetationPrivate propertyIControlDesignerAccessor.UserDataFor a description of this member, see IControlDesignerAccessor.UserData. (Inherited from Control.)
Explicit interface implemetationPrivate propertyIDataBindingsAccessor.DataBindingsFor a description of this member, see IDataBindingsAccessor.DataBindings. (Inherited from Control.)
Explicit interface implemetationPrivate propertyIDataBindingsAccessor.HasDataBindingsFor a description of this member, see IDataBindingsAccessor.HasDataBindings. (Inherited from Control.)
Explicit interface implemetationPrivate propertyIExpressionsAccessor.ExpressionsFor a description of this member, see IExpressionsAccessor.Expressions. (Inherited from Control.)
Explicit interface implemetationPrivate propertyIExpressionsAccessor.HasExpressionsFor a description of this member, see IExpressionsAccessor.HasExpressions. (Inherited from Control.)
Explicit interface implemetationPrivate methodIParserAccessor.AddParsedSubObjectFor a description of this member, see IParserAccessor.AddParsedSubObject. (Inherited from Control.)
Top

The HierarchicalDataBoundControl class is the base class used for ASP.NET controls that retrieve data from an ASP.NET hierarchical data source control and bind user-interface elements of the control to that data for display. The TreeView and Menu classes derive from HierarchicalDataBoundControl.

Page developers do not use the HierarchicalDataBoundControl class directly; instead, they use controls that derive from this class.

Controls developers extend this class to create data-bound controls that work with classes that implement the IHierarchicalDataSource interface and classes that derive from the HierarchicalDataSourceControl and HierarchicalDataSourceView classes. When deriving a class from the HierarchicalDataBoundControl class, override the PerformDataBinding method to bind the user-interface elements of your control to data retrieved by the GetData method. In most cases, the PerformDataBinding method is the only method you will override in your derived class.

For ASP.NET 2.0 data-bound controls, the PerformSelect method is the equivalent of the DataBind method, and is called to bind data at run time. The PerformSelect method calls the GetData and PerformDataBinding methods.

The following code example demonstrates how to derive a class from the HierarchicalDataBoundControl class to create a custom data-bound control. The GeneologyTree control renders a pre HTML section with a text tree for the data retrieved from an associated data source control.

using System;
using System.Collections;
using System.ComponentModel;
using System.Security.Permissions;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

namespace Samples.AspNet.CS.Controls {

    [AspNetHostingPermission(SecurityAction.Demand, 
        Level=AspNetHostingPermissionLevel.Minimal)]
    [AspNetHostingPermission(SecurityAction.InheritanceDemand, 
        Level=AspNetHostingPermissionLevel.Minimal)]
    public class GeneologyTree : HierarchicalDataBoundControl {

        private TreeNode rootNode;
        public TreeNode RootNode {
            get {
                if (rootNode == null) {
                    rootNode = new TreeNode(String.Empty);
                }
                return rootNode;
            }
        }

        private ArrayList nodes;
        public ArrayList Nodes {
            get {
                if (null == nodes) {
                    nodes = new ArrayList();
                }
                return nodes;
            }
        }
        public string DataTextField {
            get {
                object o = ViewState["DataTextField"];
                return((o == null) ? string.Empty : (string)o);
            }
            set {
                ViewState["DataTextField"] = value;
                if (Initialized) {
                    OnDataPropertyChanged();
                }
            }
        }
        private int _maxDepth = 0;
        protected override void PerformDataBinding() {
            base.PerformDataBinding();

            // Do not attempt to bind data if there is no 
            // data source set. 
            if (!IsBoundUsingDataSourceID && (DataSource == null)) {
                return;
            }

            HierarchicalDataSourceView view = GetData(RootNode.DataPath);

            if (view == null) {
                throw new InvalidOperationException
                    ("No view returned by data source control.");
            }                                  

            IHierarchicalEnumerable enumerable = view.Select();
            if (enumerable != null) {

                Nodes.Clear();

                try {
                    RecurseDataBindInternal(RootNode, enumerable, 1);
                }
                finally {

                }
            }
        }
        private void RecurseDataBindInternal(TreeNode node, 
            IHierarchicalEnumerable enumerable, int depth) {                                    

            foreach(object item in enumerable) {
                IHierarchyData data = enumerable.GetHierarchyData(item);

                if (null != data) {
                    // Create an object that represents the bound data 
                    // to the control.
                    TreeNode newNode = new TreeNode();
                    RootViewNode rvnode = new RootViewNode();

                    rvnode.Node = newNode;
                    rvnode.Depth = depth;

                    // The dataItem is not just a string, but potentially 
                    // an XML node or some other container.  
                    // If DataTextField is set, use it to determine which  
                    // field to render. Otherwise, use the first field.                     
                    if (DataTextField.Length > 0) {
                        newNode.Text = DataBinder.GetPropertyValue
                            (data, DataTextField, null);
                    }
                    else {
                        PropertyDescriptorCollection props = 
                            TypeDescriptor.GetProperties(data);

                        // Set the "default" value of the node.
                        newNode.Text = String.Empty;                        

                        // Set the true data-bound value of the TextBox, 
                        // if possible. 
                        if (props.Count >= 1) {                        
                            if (null != props[0].GetValue(data)) {
                                newNode.Text = 
                                    props[0].GetValue(data).ToString();
                            } 
                        }
                    }

                    Nodes.Add(rvnode);                    

                    if (data.HasChildren) {
                        IHierarchicalEnumerable newEnumerable = 
                            data.GetChildren();
                        if (newEnumerable != null) {                            
                            RecurseDataBindInternal(newNode, 
                                newEnumerable, depth+1 );
                        }
                    }

                    if ( _maxDepth < depth) _maxDepth = depth;

                }
            }
        }
        protected override void Render(HtmlTextWriter writer) {

            writer.WriteLine("<PRE>");                        
            int currentDepth = 1;
            int currentTextLen = 0;

            foreach (RootViewNode rvnode in Nodes) {
                if (rvnode.Depth == currentDepth) {
                    string output = "  " + rvnode.Node.Text + "  ";
                    writer.Write(output);
                    currentTextLen = currentTextLen + output.Length;
                }
                else {
                    writer.WriteLine("");
                    // Some very basic whitespace formatting 
                    int halfLine = currentTextLen / 2;
                    for (int i=0;i<halfLine;i++) {
                        writer.Write(' ');
                    }
                    writer.Write('|');
                    writer.WriteLine("");
                    ++currentDepth; 
                    currentTextLen = 0;
                    for (int j=0;j<halfLine;j++) {
                        writer.Write(' ');
                    }
                    string output = "  " + rvnode.Node.Text + "  ";
                    writer.Write(output);
                    currentTextLen = currentTextLen + output.Length;                    
                }                                                           
            }
            writer.WriteLine("</PRE>");
        }

        private class RootViewNode { 
            public TreeNode Node;
            public int Depth;
        }
    }
}

The following code example demonstrates how to use the GeneologyTree control, defined in the previous example, and bind it to an XmlDataSource control.

<%@Page language="c#" %>
<%@ Register TagPrefix="aspSample" 
    Namespace="Samples.AspNet.CS.Controls" 
    Assembly="Samples.AspNet.CS.Controls" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
  <head>
    <title>C# Example</title>
  </head>

  <body>
    <form id="Form1" method="post" runat="server">

        <aspSample:geneologytree
          id="GeneologyTree1"
          runat="server"
          datatextfield="title"
          datasourceid="XmlDataSource1" />

        <asp:xmldatasource
          id="XmlDataSource1"
          datafile="geneology.xml"          
          runat="server" />

    </form>
  </body>
</html>

The geneology.xml file accessed in the code example contains the following data.

<family>
  <member title="great-grandfather">
    <member title="grandfather" >
      <member title="child" />
      <member title="father" >
         <member title="son" />
      </member>
    </member>
  </member>
</family>

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.
Show:
© 2014 Microsoft