Bind and Show a ComboBox in a DataGridView Cell using C# and Vb.Net

Last updated: 19th June 2024

A DataGridView control in .Net is perfect for showing data in a tabular format. Its use is not limited to just displaying data, but it’s a perfect tool for doing data manipulation by binding it with a database. With its many useful features, you can make the DataGridView to perform like an Excel spreadsheet. Here this article, I'll show how to bind a ComboBox in a DataGridView control dynamically.

Update: See code for C#. I have also explained how to set the name property of each column in the DataGridView and its proper usage.

The ComboBox will show up in a Cell of a particular column when focus sets on that column. See above image. This will allow users to select value from a list of pre-define of items.

Follow these steps.

Start "Microsoft Visual Studio" and select a "New Project' from the File menu (Left Top Menu).

From "New Project" templates, select Windows Forms Application and click OK.

01) A new project appears with a "Blank Form". Click the Toolbox button (or press Ctrl+Alt+X keys) to open Toolbox window. Under All Windows Forms, find DataGridView control and "double click" it to add the control in the form.

add datagridview control in windows form

02) Select the DataGridView control and "right click" the mouse to choose Properties. In the Properties window, find the Columns property (under "Misc") and open it. Add few columns like "Employee Name", "Mobile No." etc to the Grid. (See the below Image 👇).

DataGridView Design Mode

To add the columns, simply click the Add button, which will open the "Add Column" window. You will have to add values to the first and last fields, "Name" and "Header Text".

Remember, the "Present Address" column is important for this example to work properly. Therefore, in the "Header Text" field add the text Present Address and in the Name field add "PresentAddress" (without any space).

03) Finally drag and drop a ComboBox control on the DataGridView. The ComboBox will have a list of Qualifications. So add a few items in the ComboBox. To add the values, right click the control and choose Properties. Find the Items property and add items to it.

bind combo box control to datagridview control

Set the Visible property of the ComboBox as "False". We don’t want the ComboBox to be visible when the form loads. The ComboBox will show up when the focus is on a Cell of Qualification column. Until then, it remains hidden.

Note: The "ComboBox" control should be placed on the "DataGridView" control.

Now, let’s write the code.

Code Behind (C#)

Copy and paste the below code in the code window of your application and run the application.

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace WindowsFormsApplication1
{
    public partial class frmDataGridView_Demo : Form
    {
        DataTable dtTable = new DataTable("Employee");      // CREATE A DATATABLE.

        public frmDataGridView_Demo()
        {
            InitializeComponent();
            addRows();  // ADD FEW BLANK ROWS TO START WITH.
        }

        private void addRows()
        {
            DataRow row = null;
            row = dtTable.NewRow();

            int iCntCol = 0;

            for (iCntCol = 1; iCntCol <= 10; iCntCol++)
            {
                row = dtTable.NewRow();     // ADD BLANK ROWS TO THE DATATABLE.
                dtTable.Rows.Add(row);
            }

            // ADD DATATABLE TO GRID. (WITH THE BLANK ROWS)
            dataGridView1.DataSource = dtTable;

            // ADD SOME COLOR TO THE GRID.
            dataGridView1.GridColor = Color.FromArgb(211, 222, 229);
            dataGridView1.BackgroundColor = Color.Wheat;

            dataGridView1.RowsDefaultCellStyle.BackColor = Color.AliceBlue;
            dataGridView1.RowsDefaultCellStyle.SelectionBackColor = Color.CornflowerBlue;
            dataGridView1.RowsDefaultCellStyle.SelectionForeColor = Color.White;
        }

        // CONTROL THE KEY STROKES.
        protected override bool ProcessCmdKey(ref System.Windows.Forms.Message msg, 
            System.Windows.Forms.Keys keyData)
        {
            if (keyData == Keys.Enter)
            {
                // ON ENTER KEY, GO TO THE NEXT CELL. 
                // WHEN THE CURSOR REACHES THE LAST COLUMN, CARRY IT ON TO THE NEXT ROW.

                if (ActiveControl.Name == "DataGridView1")
                {
                    // CHECK IF ITS THE LAST COLUMN
                    if (dataGridView1.CurrentCell.ColumnIndex == dataGridView1.ColumnCount - 1)
                    {
                        // GO TO THE FIRST COLUMN, NEXT ROW.
                        dataGridView1.CurrentCell = 
                            dataGridView1.Rows[dataGridView1.CurrentCell.RowIndex + 1]
                                .Cells[0];
                    }
                    else
                    {
                        // NEXT COLUMN.
                        dataGridView1.CurrentCell = 
                            dataGridView1.Rows[dataGridView1.CurrentRow.Index]
                            .Cells[dataGridView1.CurrentCell.ColumnIndex + 1];
                    }

                    return true;
                }
                else if (ActiveControl is DataGridViewTextBoxEditingControl)
                {
                    // SHOW THE COMBOBOX WHEN FOCUS IS ON A CELL 
                        CORRESPONDING TO THE "QUALIFICATION" COLUMN.
                    if (dataGridView1.Columns
                        [dataGridView1.CurrentCell.ColumnIndex].Name == "PresentAddress")
                    {
                        dataGridView1.CurrentCell = 
                            dataGridView1.Rows[dataGridView1.CurrentRow.Index]
                                .Cells[dataGridView1.CurrentCell.ColumnIndex + 1];

                        // SHOW COMBOBOX.
                        Show_Combobox(dataGridView1.CurrentRow.Index, 
                            dataGridView1.CurrentCell.ColumnIndex); 

                        SendKeys.Send("{F4}");      // DROP DOWN THE LIST.
                        return true;
                    }
                    else
                    {
                        // CHECK IF ITS THE LAST COLUMN.
                        if (dataGridView1.CurrentCell.ColumnIndex == 
                            dataGridView1.ColumnCount - 1)
                        {
                            // GO TO THE FIRST COLUMN, NEXT ROW.
                            dataGridView1.CurrentCell = 
                                dataGridView1.Rows[dataGridView1.CurrentCell.RowIndex + 1]
                                    .Cells[0];
                        }
                        else
                        {
                            // NEXT COLUMN.
                            dataGridView1.CurrentCell = 
                                dataGridView1.Rows[dataGridView1.CurrentRow.Index]
                                    .Cells[dataGridView1.CurrentCell.ColumnIndex + 1];
                        }
                        return true;
                    }
                }
                else if (ActiveControl.Name == "ComboBox1")
                {
                    // HIDE THE COMBOBOX AND ASSIGN COMBO'S VALUE TO THE CELL.
                    comboBox1.Visible = false;

                    dataGridView1.Focus();

                    // ONCE THE COMBO IS SET AS INVISIBLE, SET FOCUS BACK TO THE GRID. 
                        (IMPORTANT)
                    dataGridView1[dataGridView1.CurrentCell.ColumnIndex, 
                        dataGridView1.CurrentRow.Index].Value = comboBox1.Text;

                    dataGridView1.CurrentCell = 
                        dataGridView1.Rows[dataGridView1.CurrentRow.Index]
                            .Cells[dataGridView1.CurrentCell.ColumnIndex + 1];
                }
                else
                {
                    SendKeys.Send("{TAB}");
                }
                return true;
            }
            else if (keyData == Keys.Escape)            // PRESS ESCAPE TO HIDE THE COMBOBOX.
            {
                if (ActiveControl.Name == "ComboBox1")
                {
                    comboBox1.Text = "";
                    comboBox1.Visible = false;

                    dataGridView1.CurrentCell = 
                        dataGridView1.Rows[dataGridView1.CurrentCell.RowIndex]
                            .Cells[dataGridView1.CurrentCell.ColumnIndex];

                    dataGridView1.Focus();
                }
                return true;
            }
            else
            {
                return base.ProcessCmdKey(ref msg, keyData);
            }
        }

        private void Show_Combobox(int iRowIndex, int iColumnIndex)
        {
            // DESCRIPTION: SHOW THE COMBO BOX IN THE SELECTED CELL OF THE GRID.
            // PARAMETERS: iRowIndex - THE ROW ID OF THE GRID.
            //             iColumnIndex - THE COLUMN ID OF THE GRID.

            int x = 0;
            int y = 0;
            int Width = 0;
            int height = 0;

            // GET THE ACTIVE CELL'S DIMENTIONS TO BIND THE COMBOBOX WITH IT.
            Rectangle rect = default(Rectangle);
            rect = dataGridView1.GetCellDisplayRectangle(iColumnIndex, iRowIndex, false);
            x = rect.X + dataGridView1.Left;
            y = rect.Y + dataGridView1.Top;

            Width = rect.Width;
            height = rect.Height;

            comboBox1.SetBounds(x, y, Width, height);
            comboBox1.Visible = true;
            comboBox1.Focus();
        }
    }
}

When the focus is the fourth cell, the combo will automatically show a list of "qualification".

ComboBox in DataGridView

Vb.Net

Option Explicit On

Public Class frmDataGridView_Demo
    Dim dtTable As New DataTable("Employee")    ' CREATE A DATATABLE.

    Private Sub frmDataGridView_Demo_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        AddRows()                ' ADD FEW BLANK ROWS TO START WITH.
    End Sub

    Private Sub AddRows()
        Dim row As DataRow
        row = dtTable.NewRow

        For iCntCol = 1 To 10
            row = dtTable.NewRow        ' ADD BLANK ROWS TO THE DATATABLE.
            dtTable.Rows.Add(row)
        Next

        With DataGridView1
            .DataSource = dtTable       ' ADD DATATABLE TO GRID. (WITH THE BLANK ROWS)

            ' JUST FOR THE LOOKS.
            .GridColor = Color.FromArgb(211, 222, 229)
            .BackgroundColor = Color.Wheat

            .RowsDefaultCellStyle.BackColor = Color.AliceBlue
            .RowsDefaultCellStyle.SelectionBackColor = Color.CornflowerBlue
            .RowsDefaultCellStyle.SelectionForeColor = Color.White
        End With
    End Sub

    ' CONTROL THE KEY STROKES.
    Protected Overrides Function ProcessCmdKey(ByRef msg As System.Windows.Forms.Message, _
            ByVal keyData As System.Windows.Forms.Keys) As Boolean

        If keyData = Keys.Enter Then
            ' ON ENTER KEY, GO TO THE NEXT CELL. 
                ' WHEN THE CURSOR REACHES THE LAST COLUMN, CARRY IT ON TO THE NEXT ROW.

            If ActiveControl.Name = "DataGridView1" Then
                With DataGridView1
                    If .CurrentCell.ColumnIndex = .ColumnCount - 1 Then             ' CHECK IF ITS THE LAST COLUMN
                        .CurrentCell = .Rows(.CurrentCell.RowIndex + 1).Cells(0)    ' GO TO THE FIRST COLUMN, NEXT ROW.
                    Else
                        .CurrentCell = .Rows(.CurrentRow.Index).Cells(.CurrentCell.ColumnIndex + 1)     ' NEXT COLUMN.
                    End If
                End With

            ElseIf TypeOf ActiveControl Is DataGridViewTextBoxEditingControl Then

                ' SHOW THE COMBOBOX WHEN FOCUS IS ON A CELL CORRESPONDING TO THE "QUALIFICATION" COLUMN.
                With DataGridView1
                    If .Columns(.CurrentCell.ColumnIndex).Name = "PresentAddress" Then
                        .CurrentCell = .Rows(.CurrentRow.Index).Cells(.CurrentCell.ColumnIndex + 1)

                        ' SHOW COMBOBOX.
                        Show_Combobox(.CurrentRow.Index, .CurrentCell.ColumnIndex)
                        SendKeys.Send("{F4}")               ' DROP DOWN THE LIST.
                    Else
                        If .CurrentCell.ColumnIndex = .ColumnCount - 1 Then             ' CHECK IF ITS THE LAST COLUMN
                            .CurrentCell = .Rows(.CurrentCell.RowIndex + 1).Cells(0)    ' GO TO THE FIRST COLUMN, NEXT ROW.
                        Else
                            .CurrentCell = .Rows(.CurrentRow.Index).Cells(.CurrentCell.ColumnIndex + 1)     ' NEXT COLUMN.
                        End If
                    End If
                End With

            ElseIf ActiveControl.Name = "ComboBox1" Then
                ' HIDE THE COMBOBOX AND ASSIGN COMBO'S VALUE TO THE CELL.
                ComboBox1.Visible = False

                With DataGridView1
                    .Focus()            ' ONCE THE COMBO IS SET AS INVISIBLE, SET FOCUS BACK TO THE GRID. (IMPORTANT)
                    .Item(.CurrentCell.ColumnIndex, .CurrentRow.Index).Value = Trim(ComboBox1.Text)
                    .CurrentCell = .Rows(.CurrentRow.Index).Cells(.CurrentCell.ColumnIndex + 1)
                End With
            Else
                SendKeys.Send("{TAB}")
            End If

            Return True
        ElseIf keyData = Keys.Escape Then       ' PRESS ESCAPE TO HIDE THE COMBOBOX.
            If ActiveControl.Name = "ComboBox1" Then
                ComboBox1.Text = "" : ComboBox1.Visible = False

                With DataGridView1
                    .CurrentCell = .Rows(.CurrentCell.RowIndex).Cells(.CurrentCell.ColumnIndex)
                    .Focus()
                    Return True
                End With
            End If
        Else
            Return MyBase.ProcessCmdKey(msg, keyData)
        End If
    End Function

    Private Sub Show_Combobox(ByVal iRowIndex As Integer, ByVal iColumnIndex As Integer)
        ' DESCRIPTION: SHOW THE COMBO BOX IN THE SELECTED CELL OF THE GRID.
        ' PARAMETERS: iRowIndex - THE ROW ID OF THE GRID.
        '             iColumnIndex - THE COLUMN ID OF THE GRID.

        Dim x As Integer = 0
        Dim y As Integer = 0
        Dim Width As Integer = 0
        Dim height As Integer = 0

        ' GET THE ACTIVE CELL'S DIMENTIONS TO BIND THE COMBOBOX WITH IT.
        Dim rect As Rectangle
        rect = DataGridView1.GetCellDisplayRectangle(iColumnIndex, iRowIndex, False)
        x = rect.X + DataGridView1.Left
        y = rect.Y + DataGridView1.Top

        Width = rect.Width
        height = rect.Height

        With ComboBox1
            .SetBounds(x, y, Width, height)
            .Visible = True
            .Focus()
        End With
    End Sub
End Class

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