How can I define templatefield with check box in ASP.NET with programming?

The ItemTemplate needs to be an instance of a class which implements the ITemplate interface[^], NOT a control instance. It will need to create a new instance of the control for each data item in the parent control.

public class CheckBoxTemplate : ITemplate
{
    public void InstantiateIn(Control container)
    {
        CheckBox child = new CheckBox();
        child.DataBinding += BindData;
        container.Controls.Add(child);
    }
    
    private void BindData(object sender, EventArgs e)
    {
        CheckBox child = (CheckBox)sender;
        IDataItemContainer container = (IDataItemContainer)child.NamingContainer;
        child.Checked = DataBinder.Eval(container.DataItem, "Your Property Name Here");
    }
}

...

TemplateField tf = new TemplateField();
tf.ItemTemplate = new CheckBoxTemplate();
gridView1.Columns.Add(tf);

ITemplate.InstantiateIn(Control) Method (System.Web.UI) | Microsoft Docs[^]