How to add dynamic n checkbox columns to gridview ASP.NET

This is my grid aspx code

<asp:GridView ID="gv" runat="server" AutoGenerateColumns="false">
    <Columns>           
    </Columns>
</asp:GridView>

First of all add num number of template fields to your gridview

protected void Page_PreInit(object sender, EventArgs e)
{
    int num = Request.QueryString["num"];

    for (int i = 0; i < num; i++)
    {
        TemplateField tf = new TemplateField();
        tf.HeaderText = "Status";
        gv.Columns.Add(tf);
    }        
}

After adding template feilds, now we will add checkboxes to the gridview. We write a function to add checkboxes. Below is the code

private void AddCheckBox()
{
    int num = Request.QueryString["num"];
    for (int i = 0; i < num; i++)
    {
        foreach (GridViewRow row in gv.Rows)
        {
            if (row.RowType == DataControlRowType.DataRow)
            {
                CheckBox cb = new CheckBox();
                cb.Checked = true;                  
                row.Cells[i].Controls.Add(cb);
            }
        }
    }
}

Now place this function in your grid databound event.

protected void gv_DataBound(object sender, EventArgs e)
{
    AddCheckBox();
} 

At the end also call the function in the page load event so first time when grid loads it shows checkboxes are checked

protected void Page_Load(object sender, EventArgs e)
{
    if (!IsPostBack)
    {
        AddCheckBox();
    } 
}

To check my code: I add a bound feild to grid view and bind the grid view with a datatable:

<asp:GridView ID="gv" runat="server" AutoGenerateColumns="false">
    <Columns>
        <asp:BoundField DataField="Data" HeaderText="Data" />
    </Columns>
</asp:GridView>

and in code behind in page_load event i add the following code

 DataTable dt = new DataTable();
    dt.Columns.Add("Data");

    DataRow dr = dt.NewRow();
    dr[0] = "Test";
    dt.Rows.Add(dr);

    gv.DataSource = dt;
    gv.DataBind();

and also made 1 change in the function AddCheckBox as

for (int i = 1; i < num + 1; i++)

The above change is made because I have a databound feild at index 0 of the grid view columns so I changed it to start from 1.

and here is the result ( page output )

Data    Status  Status  Status  Status  Status  Status  Status  Status  Status  Status
Test    Checked Checked Checked Checked Checked Checked Checked Checked Checked Checked

Checked is used for checkbox is checked