TreeView Hot Track Backcolor FullRow

[squatman]

Hi there,

I've been trying to customise the background colour of a TreeView node when the mouse hovers over it. I've been looking into the HotTracking property for this, and I also want it to fill the full width of the nodes "row".

With the following code I've managed to customise the colour of the node's text whilst the mouse is hovered (HotTracked).

Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
 
        Me.TreeView1.BorderStyle = System.Windows.Forms.BorderStyle.FixedSingle
        Me.TreeView1.FullRowSelect = True
        Me.TreeView1.HideSelection = False
        Me.TreeView1.HotTracking = True
        Me.TreeView1.ShowLines = False
 
        Me.TreeView1.DrawMode = TreeViewDrawMode.OwnerDrawText
    End Sub
 
    Private Sub treeView1_DrawNode(ByVal sender As Object, ByVal e As DrawTreeNodeEventArgs) Handles TreeView1.DrawNode
        Dim font As Font = If(e.Node.NodeFont, e.Node.TreeView.Font)
        Dim foreColor As Color = e.Node.ForeColor
 
        If e.State = TreeNodeStates.Hot Then
            e.Node.ForeColor = Color.Red
        Else
            e.Node.ForeColor = Color.Blue
        End If
 
        Dim backColor As Color = e.Node.BackColor
 
        'If e.State = TreeNodeStates.Hot Then
        '    e.Node.BackColor = Color.Red
        'Else
        '    e.Node.BackColor = Color.Blue
        'End If
 
        TextRenderer.DrawText(e.Graphics, e.Node.Text, font, e.Bounds, foreColor, backColor, TextFormatFlags.GlyphOverhangPadding)
    End Sub

This gives the following result:




I've previously been using a bit of code that allows the Windows OS theme to be applied to TreeViews:

<DllImport("uxtheme.dll", CharSet:=CharSet.Unicode, ExactSpelling:=True)>
    Public Function SetWindowTheme(ByVal hWnd As IntPtr, ByVal appName As String, ByVal partList As String) As Integer
    End Function
 
SetWindowTheme(Me.TreeView1.Handle, "explorer", Nothing)

This does highlight the full width of the nodes "row" when the mouse hovers over:



I tried using the following code:

If e.State = TreeNodeStates.Hot Then
            e.Node.BackColor = Color.Red
        Else
            e.Node.BackColor = Color.Blue
        'End If

But this just changes the area behind the width of the node's text, not it's full row width.

Can anyone suggest how I can target the full row widths colour please. Do I need draw a rectangle or something to the size I need?

Any help with this would be greatly appreciated, thanks in advance.

[Poppa Mintin]

First, I'm surprised that your question hasn't been answered before now, such a long delay is most unusual in this forum.

Sadly I don't have an answer, I do have a query.
In your first code snippet, line 13: I wonder why you don't get an error 'If' without a 'Then' ?


Poppa

(At least this will bring the question back to the fore)

[jmcilhinney]

In your first code snippet, line 13: I wonder why you don't get an error 'If' without a 'Then' ?

That's because it's an If operator, not an If statement. C# has the ternary operator and the null-coalescing operator:

var t = true;
var f = false;
 
var a = t ? "yes" : "no"; // a will be "yes"
var b = f ? "yes" : "no"; // b will be "no"
 
string n = null;
string s = "Hello";
 
var c = n ?? "Goodbye"; // c will be "Goodbye"
var d = s ?? "Goodbye"; // d will be "Hello"

VB has If operators that do the same things. If with three operands is equivalent to the ternary operator (a better version of the IIf function) and If with two operands, as in post #1, is equivalent to the null coalescing operator. Basically, return the first operand if it is not Nothing, otherwise return the second operand.

Dim t = True
Dim f = False
 
Dim a = If(t, "yes", "no") 'a will be "yes"
Dim b = If(f, "yes", "no") 'b will be "no"
 
Dim n As String
Dim s = "Hello"
 
Dim c = If(n, "Goodbye") 'c will be "Goodbye"
Dim d = If(s, "Goodbye") 'd will be "Hello"

[squatman]

Well you two just got my hopes right up when I saw replies to this! Dam you haha.

[Delaney]

from here :http://vbcity.com/forums/t/164681.aspx

This should give what you want (tested on VB 2010)

Me.TreeView1.HotTracking = False
Me.TreeView1.ShowLines = False
Me.TreeView1.FullRowSelect = True
 
Private previousNode As TreeNode = Nothing
 
Private Sub TreeView1_NodeMouseHover(ByVal sender As Object, ByVal e As System.Windows.Forms.TreeNodeMouseHoverEventArgs) Handles TreeView1.NodeMouseHover
        If previousNode IsNot Nothing Then
            previousNode.ForeColor = Nothing
            previousNode.BackColor = Nothing
        End If
 
        e.Node.ForeColor = Color.FromKnownColor(KnownColor.HighlightText)
        e.Node.BackColor = Color.FromKnownColor(KnownColor.Highlight)
 
        previousNode = e.Node
End Sub

[squatman]

Delaney,

Thank you for your reply I really appreciate it.

Unfortunately this only sort of works, it only changes colour when you mouseover the actual text not the nodes full row width. Also it is strangely quite slow to change the colour, unlike "HotTracking" which is instant.

The search continues!

[Poppa Mintin]

Thanks John,

That's very enlightening, something else for my collection of snippets.


Poppa


I just discovered that I didn't send this post !

Pop.

[Delaney]

Delaney,

Thank you for your reply I really appreciate it.

Unfortunately this only sort of works, it only changes colour when you mouseover the actual text not the nodes full row width. Also it is strangely quite slow to change the colour, unlike "HotTracking" which is instant.

The search continues!

EDIT : rereading your post make me discover I didn't fully understand it the first time (I thought that for you it didn't highlight the full row). So I discard my previous answer.