RadTreeView in RadDropDownList

[Carsten]

Hi,

We have a RadTreeView in our RadDropDownList based on the sample found here:
http://www.telerik.com/community/forums/winforms/combobox-and-listbox/treeview-in-dropdown.aspx

But we seem to have some issues with it:

If the 'Arrow Button' is clicked while the popup is open, then the 'arrow button' gets stuck as if it's still pressed but the popup itself is not showing. Once in this mode, any further clicks on the arrow button will display the popup and immediately close it again.
This behavior is also reproducible in the sample attached in the forum post.

I hope anyone has a way of getting around this.

Thank you in advance.

Carsten.

[Dess | Tech Support Engineer, Principal]

Hello Carsten,

Thank you for contacting Telerik Support.

In order to apply the provided solution to RadDropDownList and the embedded RadTreeView in its pop up, you may use the following approach:

RadHostItem h;
RadTreeView radTreeView1;

public Form1()
{
    InitializeComponent();

    this.radTreeView1 = new RadTreeView();
    for (int i = 0; i < 50; i++)
    {
        RadTreeNode node = new RadTreeNode();
        node.Text = "Node" + i.ToString();
        this.radTreeView1.Nodes.Add(node);
    }

    this.radTreeView1.Dock = DockStyle.Fill;
    h = new RadHostItem(this.radTreeView1);
    this.radDropDownList1.DropDownMinSize = new Size(this.radDropDownList1.Width, 60);
    this.radTreeView1.SelectedNodeChanged += radTreeView1_SelectedNodeChanged;

    if (this.radDropDownList1.DropDownListElement.ListElement.Parent != null)
    {
        this.radDropDownList1.DropDownListElement.ListElement.Children.Insert(0, h);
    }
}

private void radTreeView1_SelectedNodeChanged(object sender, RadTreeViewEventArgs e)
{
    this.radDropDownList1.DropDownListElement.ClosePopup();
    this.radDropDownList1.Text = this.radTreeView1.SelectedNodes[0].Text;
}

Please note that the referred solution in the forum thread is not a generic solution and it may not work correctly in all scenarios. Feel free to modify the approach according to your needs.

I hope this information helps. Should you have further questions, I would be glad to help.

Regards,
Desislava
Telerik

[Carsten]

Hi Desislava,

That's awesome, it seems to work, thank you so much!

[Dess | Tech Support Engineer, Principal]

Hello Carsten,

I am glad that the issue you were facing is now resolved. Please do not hesitate to contact us if you have any additional questions.

Regards,
Desislava
Telerik

[Peter]

Hi All, 

I was able to integrate a RadTreeView into the RadDropDownList with the approach suggested by Desislava. 

Can you give me an example how to enable scrolling by mousewheel and arrow keys? 

Thank you very much in advance,

Peter 

[Dess | Tech Support Engineer, Principal]

Hello Peter,

Thank you for writing.

You can achieve scrolling on mouse wheel for the RadTreeView hosted in the DropDownPopupForm following the approach below:

RadHostItem h;
RadTreeView radTreeView1;
MethodInfo mi;

public Form1()
{
    InitializeComponent();
    this.radTreeView1 = new RadTreeView();
    for (int i = 0; i < 50; i++)
    {
        RadTreeNode node = new RadTreeNode();
        node.Text = "Node" + i.ToString();
        this.radTreeView1.Nodes.Add(node);
    }
    mi = radTreeView1.TreeViewElement.GetType().GetMethod("ProcessMouseWheel",
        BindingFlags.NonPublic | BindingFlags.Instance);

    this.radTreeView1.Dock = DockStyle.Fill;
    h = new RadHostItem(this.radTreeView1);
    this.radDropDownList1.DropDownMinSize = new Size(this.radDropDownList1.Width, 60);
    this.radTreeView1.SelectedNodeChanged += radTreeView1_SelectedNodeChanged;

    if (this.radDropDownList1.DropDownListElement.ListElement.Parent != null)
    {
        this.radDropDownList1.DropDownListElement.ListElement.Children.Insert(0, h);
    }

    this.radDropDownList1.PopupOpened += radDropDownList1_PopupOpened;
}

private void radDropDownList1_PopupOpened(object sender, EventArgs e)
{
    RadDropDownListElement ddle = sender as RadDropDownListElement;
    ddle.Popup.MouseWheel -= ddle_MouseWheel;
    ddle.Popup.MouseWheel += ddle_MouseWheel;
}

private void ddle_MouseWheel(object sender, MouseEventArgs e)
{
    DropDownPopupForm popup = sender as DropDownPopupForm;
    RadTreeView tree = popup.Controls[0] as RadTreeView;
    if (tree != null && mi != null)
    {
        mi.Invoke(tree.TreeViewElement, new object[] { e });
    }
}

private void radTreeView1_SelectedNodeChanged(object sender, RadTreeViewEventArgs e)
{
    this.radDropDownList1.DropDownListElement.ClosePopup();
    this.radDropDownList1.Text = this.radTreeView1.SelectedNodes[0].Text;
}

I hope this information helps. Should you have further questions, I would be glad to help.

Regards,
Desislava
Telerik

 

 

[Mudasser]

Hi,

We need to search through the RadTreeView nodes using the RadDropDownList control with DropdownStyle = DropDown.

Is there anyway that as we write any text in the text area of DropDownList and it automatically show the relevant tree nodes in the popup?

 Thanks

Mudasser Hameed

[Dess | Tech Support Engineer, Principal]

Hello Mudasser,

Thank you for writing.
 
You can subscribe to the DropDownListElement.TextBox.TextChanged event and filter the tree view by setting the RadTreeView.Filter property:

RadHostItem h;
RadTreeView radTreeView1;
MethodInfo mi;

public Form1()
{
    InitializeComponent();
    this.radTreeView1 = new RadTreeView();
    for (int i = 0; i < 50; i++)
    {
        RadTreeNode node = new RadTreeNode();
        node.Text = "Node" + i.ToString();
        this.radTreeView1.Nodes.Add(node);
    }
    mi = radTreeView1.TreeViewElement.GetType().GetMethod("ProcessMouseWheel",
        BindingFlags.NonPublic | BindingFlags.Instance);

    this.radTreeView1.Dock = DockStyle.Fill;
    h = new RadHostItem(this.radTreeView1);
    this.radDropDownList1.DropDownMinSize = new Size(this.radDropDownList1.Width, 60);
    this.radTreeView1.SelectedNodeChanged += radTreeView1_SelectedNodeChanged;

    if (this.radDropDownList1.DropDownListElement.ListElement.Parent != null)
    {
        this.radDropDownList1.DropDownListElement.ListElement.Children.Insert(0, h);
    }

    this.radDropDownList1.PopupOpened += radDropDownList1_PopupOpened;
    this.radDropDownList1.DropDownListElement.TextBox.TextChanged += TextBox_TextChanged;
}

private void TextBox_TextChanged(object sender, EventArgs e)
{
    this.radDropDownList1.DropDownListElement.ShowPopup();
    this.radTreeView1.Filter = this.radDropDownList1.DropDownListElement.TextBox.Text;
}

private void radDropDownList1_PopupOpened(object sender, EventArgs e)
{
    RadDropDownListElement ddle = sender as RadDropDownListElement;
    ddle.Popup.MouseWheel -= ddle_MouseWheel;
    ddle.Popup.MouseWheel += ddle_MouseWheel;
}

private void ddle_MouseWheel(object sender, MouseEventArgs e)
{
    DropDownPopupForm popup = sender as DropDownPopupForm;
    RadTreeView tree = popup.Controls[0] as RadTreeView;
    if (tree != null && mi != null)
    {
        mi.Invoke(tree.TreeViewElement, new object[] { e });
    }
}

private void radTreeView1_SelectedNodeChanged(object sender, RadTreeViewEventArgs e)
{
    this.radDropDownList1.DropDownListElement.ClosePopup();
    this.radDropDownList1.Text = this.radTreeView1.SelectedNodes[0].Text;
}

I hope this information helps. Should you have further questions I would be glad to help.

 

Regards,
Dess
Telerik

[Gilbert]

Please Help！When I use a DataTable object as the RadTreeView`s DataSource the treeview doesn`t show when the RadDropDownList popup.

[Dess | Tech Support Engineer, Principal]

Hello, Gilbert,    

If you add the RadTreeView programmatically and bind it to a DataTable, it is necessary to initialize its BindingContext before setting the DataSource property. 

this.radTreeView1 = new RadTreeView();
DataTable dt = new DataTable();
dt.Columns.Add("Id",typeof(int));
dt.Columns.Add("Name",typeof(string));
for (int i = 0; i < 10; i++)
{
    dt.Rows.Add(i,"Node"+i);
}
this.radTreeView1.BindingContext = new BindingContext();
this.radTreeView1.DataSource = dt;
this.radTreeView1.DisplayMember = "Name";
this.radTreeView1.ValueMember = "Id";

I hope this information helps. If you have any additional questions, please let me know. 
 

 

Regards,
Dess
Progress Telerik

[Gilbert]

Hi，Dess

It works.Thank you for your help!