Tooltip on combobox dropdown items in C#.NET

Lakshmi,
There are 2 ways by which you can see tooltips for the dropdown items of a combobox.
1. Create a customControl - If you desire to have your style, font, background for tooltips
2. Override DrawItem of combobox
I have taken Item 2 and here's a simple example. You may need to play around with the X & Y xo-orinates to get things right

        private void cbLongTexts_DrawItem(object sender, DrawItemEventArgs e)
        {
            if (e.Index == -1)
            {
                return;
            }
 
            //cbLongTexts.PointToClient(new Point(Control.MousePosition.X + e.Bounds.Width, Control.MousePosition.Y + e.Bounds.Height))
            Point p = new Point(cbLongTexts.Location.X, cbLongTexts.Location.Y + cbLongTexts.Height);
            //user mouse is hovering over this drop-down item, update its data   
            if ((e.State & DrawItemState.Selected) == DrawItemState.Selected)
            {
                // this tooltip simply shows the displayed text to the right of the drop-down  box, customize as needed   
                toolTip1.Show(cbLongTexts.Items[e.Index].ToString(), this,
                    //new Point(e.Bounds.X + e.Bounds.Width, e.Bounds.Y));
                    p);
            }
            e.DrawBackground();
            // draw text strings   
            e.Graphics.DrawString(
                cbLongTexts.Items[e.Index].ToString(),
                e.Font,
                Brushes.Black, new Point(e.Bounds.X, e.Bounds.Y));   
        }

          Here are some things that you may want to know before you use this code
          1. Make sure the Combobox DrawMode is set to "OwnerDrawFixed"
          2. Move over to the events section of the combobox (In my case it was cbLongTexts) and look for the event DrawItem
          and the rest of what needs to be done within the function is in there for you to witness and execute
          Have fun.
          
Let me know if you need anything more

Your code is perfect, it will show the tooltip once you selected the item, but what Lakshmi need is, she needs to display the tooltip on mouse hover of the selection list as shown in the image.

I have uploaded the sample screen shot of what i would like to say. Just view the image, you will come to know.
Above code will display the tool tip after the selection of item from the list. Once you selected the item, if you move your mouse over the combo box, tooltip will be shown.
But it wont show the tooltip when you move the mouse over the selection items of the combo box as shown in the image.
 

Lakshmi you can customize the ToolTip to this extend, might be another way also...

Private Sub ComboBox1_MouseHover(ByVal sender As Object, ByVal e As System.EventArgs) Handles ComboBox1.MouseHover
   If ComboBox1.SelectedItem <> "" Then
      Dim ToolTip1 As New ToolTip
      Dim caption As String = "Selected value is: " & ComboBox1.SelectedItem
      Dim lbl As New Label
      lbl.BackColor = System.Drawing.Color.RoyalBlue.RosyBrown
      lbl.Text = caption
      ComboBox1.Controls.Add(lbl)
      ComboBox1.Controls.Item(0).BringToFront()
      ComboBox1.Controls.Item(0).Width = 200
      ComboBox1.Controls.Item(0).Height = 100
      ToolTip1.SetToolTip(ComboBox1, "")
      ToolTip1.AutoPopDelay = 5000
      ToolTip1.InitialDelay = 200
      ToolTip1.ReshowDelay = 100
      ToolTip1.ShowAlways = True
   End If
End Sub
Private Sub Form1_MouseMove(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles MyBase.MouseMove
   ComboBox1.Controls.Clear()
End Sub

I dont understood what you trying to say?

At any point of logic there will a value binded to the CombobBox,

that will a SelectedItem, SelectedText, SelectedValue or simply Text.

you can use following....

Dim caption As String = vbCrLf & "Selected value is: " & vbCrLf & ComboBox1.Text & vbCrLf
Dim caption As String = "Selected value is: " & ComboBox1.SelectedItem
Dim caption As String = "Selected value is: " & ComboBox1.SelectedText
Dim caption As String = "Selected value is: " & ComboBox1.SelectedValue

again this code also shows the tooltip after you select the item from the combo box and not on the fly.
This event will fire on mouse hover of the combo box and not on mouse hover of the selection list.
I tried this already.

Mani, yes i agreed with your definition about tooltip.

My first reply with an example is because of you said its not supported.

Now about MouseHover, did you tried to test the code before posting replys.

You can use MouseHover event to show the toolitips also.

Private Sub ComboBox1_MouseHover(ByVal sender As Object, ByVal e As System.EventArgs) Handles ComboBox1.MouseHover
   Dim ToolTip1 As New ToolTip
   Dim caption As String = "Selected value is: " & ComboBox1.SelectedText
   ToolTip1.SetToolTip(ComboBox1, caption)
   ToolTip1.AutoPopDelay = 5000
   ToolTip1.InitialDelay = 200
   ToolTip1.ReshowDelay = 100
   ToolTip1.ShowAlways = True
End Sub

But am not sure you can make a customised ToolTip with colors, font etc with VS 2003.

ya that's true it works only after selecting the item in the combobox rather than on mouse hover on the dropdown items.  so i can conclude that it is not possible to have a tooltip on hover of dropdown items of a combobox. Thank you all for your help.

Your code will work fine. But whats the issue  is, It will show the tooltip, after you selected the items from the dropdown list and not on hover of the mouse.
 
Window that popup on hover of the mouse is called tool tip.
Thats why i preferred to have a label to display the item name fully.
 
 
 
 
 

yes.. its supported..

Private Sub ComboBox1_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles ComboBox1.SelectedIndexChanged
   Dim ToolTip1 As New ToolTip
   ToolTip1.SetToolTip(ComboBox1, ComboBox1.SelectedItem)
   ToolTip1.AutoPopDelay = 5000
   ToolTip1.InitialDelay = 1000
   ToolTip1.ReshowDelay = 500
   ToolTip1.ShowAlways = True
End Sub
 
but if you need formating refer link

Tooltip is not supported in combobox of windows application. I was talking about dropdown list of web application.
You can put a label next to combobox and display the items text in it after selecting the item from the combobox.
Thats it you cand do.

Visual studio .NET 2003 and its windows application

Which version of .NET you are using ?
Is it a Windows Application or Web Application ?

I have tried using the below one but there is no Attributes for combobox items. :(
for (int i = 0; i < comboxBox1.Items.Count; i++)
{
//DropDownList1.Items[i].Attributes.Add("title", DropDownList1.Items[i].Text);
}

Change the for loop as below.
for (int i = 0; i < DropDownList1.Items.Count; i++)
{
DropDownList1.Items[i].Attributes.Add("title", DropDownList1.Items[i].Text);
}

Here is my code -  i couldn't see any attribute for combobox items as you specified for a list box. please help. Thanks

using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;

namespace Combobox_tooltip
{
    ///

    /// Summary description for Form1.
    ///

    public class Form1 : System.Windows.Forms.Form
    {
        private ToolTip toolTip1;
        private System.Windows.Forms.ComboBox comboBox1;
        private System.ComponentModel.IContainer components;

        public Form1()
        {
            //
            // Required for Windows Form Designer support
            //
            InitializeComponent();

            //
            // TODO: Add any constructor code after InitializeComponent call
            //
        }

        ///

        /// Clean up any resources being used.
        ///

        protected override void Dispose( bool disposing )
        {
            if( disposing )
            {
                if (components != null)
                {
                    components.Dispose();
                }
            }
            base.Dispose( disposing );
        }

        #region Windows Form Designer generated code
        ///

        /// Required method for Designer support - do not modify
        /// the contents of this method with the code editor.
        ///

        private void InitializeComponent()
        {
            this.components = new System.ComponentModel.Container();
            this.comboBox1 = new System.Windows.Forms.ComboBox();
            this.toolTip1 = new System.Windows.Forms.ToolTip(this.components);
            this.SuspendLayout();
            //
            // comboBox1
            //
            this.comboBox1.Items.AddRange(new object[] {
                                                           "ramya",
                                                           "lakshmiramya",
                                                           "abcdefghijklmnopqrstuvwxyz",
                                                           "abcdefghijklm",
                                                           "abcdefghijklmraqeewf",
                                                           "yxwvutsrqponmlkjihgf",
                                                           "zyxwvutsrqponmlkjihgfedcba"});
            this.comboBox1.Location = new System.Drawing.Point(64, 56);
            this.comboBox1.Name = "comboBox1";
            this.comboBox1.Size = new System.Drawing.Size(121, 21);
            this.comboBox1.TabIndex = 0;
            this.comboBox1.Text = "comboBox1";
            this.toolTip1.SetToolTip(comboBox1,comboBox1.Text);
            this.comboBox1.MouseHover += new System.EventHandler(this.comboBox1_MouseHover);
            this.comboBox1.SelectedIndexChanged += new System.EventHandler(this.comboBox1_SelectedIndexChanged);
            //
            // toolTip1
            //
            this.toolTip1.AutoPopDelay = 0;
            this.toolTip1.InitialDelay = 0;
            this.toolTip1.ReshowDelay = 0;
            this.toolTip1.ShowAlways = true;
            //
            // Form1
            //
            this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
            this.ClientSize = new System.Drawing.Size(292, 266);
            this.Controls.Add(this.comboBox1);
            this.Name = "Form1";
            this.Text = "Form1";
            this.ResumeLayout(false);

        }
        #endregion

        ///

        /// The main entry point for the application.
        ///

        [STAThread]
        static void Main()
        {
            Application.Run(new Form1());
        }

        private void comboBox1_SelectedIndexChanged(object sender, System.EventArgs e)
        {
            toolTip1.SetToolTip(comboBox1,comboBox1.SelectedItem.ToString());
        }

        private void comboBox1_MouseHover(object sender, EventArgs e)
        {
            MessageBox.Show(comboBox1.SelectedText);
        }
        //
        // This method binds tooltip with a dropdown/ any list control
        //
        public static void BindTooltip(ListControl lc)
        {
            for (int i = 0; i < lc.Items.Count; i++)
            {
                lc.Items[i].Attributes.Add("title", lc.Items[i].Text);
            }
        }
    }
}

Thanks for your reply..
can we have the same for combobox??

Below code will help you to achieve your goal.
//
// This method binds tooltip with a dropdown/ any list control
//
public static void BindTooltip(ListControl lc) { for (int i = 0; i < lc.Items.Count; i++)
    {
        lc.Items[i].Attributes.Add("title", lc.Items[i].Text);
    }
}