Sometimes, it is not practical to statically predefine the tree structure due to data size or custom content that depends on user input. Because of this, the TreeView control supports dynamic node population. When the PopulateOnDemand property for a node is set to true , that node gets populated at run time when the node is expanded.
To populate a node dynamically, first set the PopulateOnDemand property for the node to true. Next, define an event-handling method for the TreeNodePopulate event that populates the node programmatically. A typical event-handling method retrieves node data from a data source, places the data into a node structure, and then adds the node structure to the ChildNodes collection of the node being populated.
A node structure is created by adding TreeNode objects to the ChildNodes collection of a parent node. When the PopulateOnDemand property for a node is set to true , the node must be populated dynamically. Contents Exit focus mode. Tree View Constructor Reference Is this page helpful? Please rate your experience Yes No. Any additional feedback? Namespace: System. WebControls Assembly: System. Microsoft makes no warranties, express or implied, with respect to the information provided here.
Gets a collection of TreeNode objects that represents the root nodes in the TreeView control. The following code example demonstrates how to use the Nodes property to traverse the tree. Use the Nodes property to get a TreeNodeCollection object that contains all the root nodes in the tree.
This collection is commonly used to quickly iterate through all the root nodes, or to access a specific root node in the tree. A typical tree structure has only one root node; however, you can add multiple root nodes to the TreeView control.
Gets or sets a value indicating whether node data is populated on demand from the client. Gets a value that specifies the ASP. Gets or sets a value indicating whether expansion node indicators are displayed.
Gets or sets the skin to apply to the control. Gets or sets the tab index of the Web server control. Gets the name of the control tag. Gets or sets a reference to the template that contains this control. Gets or sets the text displayed when the mouse pointer hovers over the Web server control. Gets the unique, hierarchically qualified identifier for the server control. Gets or sets the view-state mode of this control. Gets or sets a value indicating whether the control is rendered as UI on the page.
Gets or sets the width of the Web server control. AddedControl Control, Int AddParsedSubObject Object. ApplyStyle Style.
ApplyStyleSheetSkin Page. Applies the style properties defined in the page style sheet to the control.
Begins design-time tracing of rendering data. BuildProfileTree String, Boolean. Deletes the control-state information for the server control's child controls.
Deletes the view-state information for all the server control's child controls. Sets the initialized state of the data-bound control. CopyBaseAttributes WebControl. DataBind Boolean. Binds a data source to the server control's child controls. Enables a server control to perform final clean up before it is released from memory. Ends design-time tracing of rendering data. Creates an identifier for controls that do not have an identifier assigned. Equals Object.
Determines whether the specified object is equal to the current object. Inherited from Object. FindControl String. FindControl String, Int FindNode String.
Sets input focus to a control. GetData String. Gets design-time data for a control. Serves as the default hash function. GetRouteUrl Object. Gets the URL that corresponds to a set of route parameters. GetRouteUrl String, Object. Gets the URL that corresponds to a set of route parameters and a route name. Determines if the server control contains any child controls.
Returns a value indicating whether events are registered for the control or any child controls. Determines if the server control holds only literal content. LoadControlState Object. LoadViewState Object. MapPathSecure String. Retrieves the physical path that a virtual path, either absolute or relative, maps to. Sets the state of the control in view state as successfully bound to data. MergeStyle Style. OnDataBinding EventArgs. OnDataBound EventArgs.
OnInit EventArgs. OnLoad EventArgs. Sets the initialized state of the data-bound control before the control is loaded. OnPreRender EventArgs. OnUnload EventArgs. OpenFile String. Retrieves data from the associated data source. Assigns any sources of the event and its information to the control's parent. RaiseCallbackEvent String. RaisePostBackEvent String. RemovedControl Control. Render HtmlTextWriter. Renders the control to the specified HTML writer. RenderChildren HtmlTextWriter.
RenderContents HtmlTextWriter. RenderControl HtmlTextWriter. Gets the control adapter responsible for rendering the specified control. ResolveClientUrl String. Gets a URL that can be used by the browser. ResolveUrl String. Converts a URL into one that is usable on the requesting client.
Sets design-time data for a control. SetTraceData Object, Object. Returns a string that represents the current object. ValidateDataSource Object. Verifies that the object a data-bound control binds to is one it can work with. Occurs when the server control binds to a data source. Occurs after the server control binds to a data source. Occurs when the server control is initialized, which is the first step in its lifecycle.
Occurs when the server control is unloaded from memory. GetAttribute String. Gets an attribute of the Web control with the specified name. SetAttribute String, String. Sets an attribute of the Web control to the specified name and value.
SetOwnerControl Control. Enables selection to be persisted in data controls that support selection and paging. FindDataSourceControl Control. Returns the data source that is associated with the data control for the specified control.
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