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TreeView.ShowLines Property

Gets or sets a value indicating whether lines are drawn between tree nodes in the tree view control.

Namespace:  System.Windows.Forms
Assembly:  System.Windows.Forms (in System.Windows.Forms.dll)

Public Property ShowLines As Boolean

Property Value

Type: System.Boolean
true if lines are drawn between tree nodes in the tree view control; otherwise, false. The default is true.

If ShowLines is set to true, the FullRowSelect property is ignored.

The following code example illustrates a customized TreeView. By inheriting the TreeView class, this custom version has all the functionality of a typical TreeView. Changing various property values in the constructor provides a unique appearance. Because the ShowPlusMinus property is set to false, the customized control also overrides the OnAfterSelect method so that nodes can be expanded and collapsed when they are clicked.

A control that is customized in this way can be used throughout an organization, making it easy to provide a consistent interface without requiring the control properties to be specified in each individual project.

Public Class CustomizedTreeView
    Inherits TreeView

    Public Sub New()
        ' Customize the TreeView control by setting various properties.
        BackColor = System.Drawing.Color.CadetBlue
        FullRowSelect = True
        HotTracking = True
        Indent = 34
        ShowPlusMinus = False 

        ' The ShowLines property must be false for the FullRowSelect  
        ' property to work.
        ShowLines = False 
    End Sub 'New 

    Protected Overrides Sub OnAfterSelect(ByVal e As TreeViewEventArgs)
        ' Confirm that the user initiated the selection. 
        ' This prevents the first node from expanding when it is 
        ' automatically selected during the initialization of  
        ' the TreeView control. 
        If e.Action <> TreeViewAction.Unknown Then 
            If e.Node.IsExpanded Then
            End If 
        End If 

        ' Remove the selection. This allows the same node to be 
        ' clicked twice in succession to toggle the expansion state.
        SelectedNode = Nothing 
    End Sub 'OnAfterSelect

End Class 'CustomizedTreeView 

.NET Framework

Supported in: 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

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.

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