Column Header CheckBox in DataGridView (Winfoms)

Introduction

This article will explains about creating & displaying Column Header CheckBox in winforms DataGridView.

Background

Bydefault DataGridView doen't supports column header chekbox, for this we need to write a class which is inherited by DataGridViewColumnHeaderCell class.

1) Add a boolean propery named CheckAll in that class to maintain the seleced state of Header checkbox.

2) override default implemention of Paint method. In this method, drawing the CheckBox at column Header.

3) override its OnMouseClick event. Here handle the click event of header checkbox.

I have created class named DGVColumnHeader as follows...

    class DGVColumnHeader : DataGridViewColumnHeaderCell
    {
        private Rectangle CheckBoxRegion;
        private bool checkAll = false;

        protected override void Paint(Graphics graphics,
            Rectangle clipBounds, Rectangle cellBounds, int rowIndex,
            DataGridViewElementStates dataGridViewElementState,
            object value, object formattedValue, string errorText,
            DataGridViewCellStyle cellStyle, DataGridViewAdvancedBorderStyle advancedBorderStyle,
            DataGridViewPaintParts paintParts)
        {

            base.Paint(graphics, clipBounds, cellBounds, rowIndex, dataGridViewElementState, value,
                formattedValue, errorText, cellStyle, advancedBorderStyle, paintParts);

            graphics.FillRectangle(new SolidBrush(cellStyle.BackColor), cellBounds);

            CheckBoxRegion = new Rectangle(
                cellBounds.Location.X + 1,
                cellBounds.Location.Y + 2,
                25, cellBounds.Size.Height - 4);


            if (this.checkAll)
                ControlPaint.DrawCheckBox(graphics, CheckBoxRegion, ButtonState.Checked);
            else
                ControlPaint.DrawCheckBox(graphics, CheckBoxRegion, ButtonState.Normal);

            Rectangle normalRegion =
                new Rectangle(
                cellBounds.Location.X + 1 + 25,
                cellBounds.Location.Y,
                cellBounds.Size.Width - 26,
                cellBounds.Size.Height);

            graphics.DrawString(value.ToString(), cellStyle.Font, new SolidBrush(cellStyle.ForeColor), normalRegion);
        }

        protected override void OnMouseClick(DataGridViewCellMouseEventArgs e)
        {
            //Convert the CheckBoxRegion 
            Rectangle rec = new Rectangle(new Point(0, 0), this.CheckBoxRegion.Size);
            this.checkAll = !this.checkAll;
            if (rec.Contains(e.Location))
            {
                this.DataGridView.Invalidate();
            }
            base.OnMouseClick(e);
        }

        public bool CheckAll
        {
            get { return this.checkAll; }
            set { this.checkAll = value; }
        }
    }
    

        //Create the object of DGVColumnHeader 
        DGVColumnHeader dgvColumnHeader;
        private void Form1_Load(object sender, EventArgs e)
        {
            //initialize DGVColumnHeader object
            dgvColumnHeader = new DGVColumnHeader();
            
            //Add columns dynamically  to gridview
            dataGridView1.Columns.Insert(0, new DataGridViewCheckBoxColumn());
            dataGridView1.Columns[0].HeaderCell = dgvColumnHeader;
            
            //Data Binding 
            DataTable dt = new DataTable();
            dt.Columns.Add("1");
            dt.Columns.Add("2");
            dt.Rows.Add("100", "101");
            dt.Rows.Add("102", "103");
            dataGridView1.DataSource = dt;
        }
        

        private void dataGridView1_ColumnHeaderMouseClick(object sender, DataGridViewCellMouseEventArgs e)
        {
            if (e.ColumnIndex == 0)
            {
                for (int i = 0; i < dataGridView1.Rows.Count; i++)
                {
                    dataGridView1.Rows[i].Cells[0].Value = dgvColumnHeader.CheckAll;
                }
            }
        }
      

        private void dataGridView1_CellClick(object sender, DataGridViewCellEventArgs e)
        {
            if (e.ColumnIndex == 0)
            {
                for (int i = 0; i < this.dataGridView1.RowCount; i++)
                {
                    //Escalate Editmode
                    this.dataGridView1.EndEdit();
                    string re_value = this.dataGridView1.Rows[i].Cells[0].EditedFormattedValue.ToString();
                    this.dataGridView1.Rows[i].Cells[0].Value = "true";
                }
            }
        }

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)