I have gridview which fetches data from sql server, i have action buttons edit delete update and cancel

Question

I have a gridview which fetches data from SQL server, I have action buttons edit delete update and cancel.

I have a code but I don't know how to implement iti.e click events for the edit delete cancel update operations.

asp code

<Columns>
<asp:BoundField DataField="group" HeaderText="group" SortExpression="group" />
<asp:BoundField DataField="key" HeaderText="key" SortExpression="key" />
<asp:BoundField DataField="label" HeaderText="label" SortExpression="label" />
<asp:CommandField ButtonType="Button" CancelText="" HeaderText="Action" ShowDeleteButton="True" ShowEditButton="True" />
</Columns>

code behind C#

 protected void GridView_RowEditing1(object sender, GridViewEditEventArgs e)
    {
        GridView.EditIndex = e.NewEditIndex;
        BindGrid();
    }

    protected void GridView_RowDeleting(object sender, GridViewDeleteEventArgs e)
    {

        SqlConnection con = new SqlConnection(connectionString);
        GridViewRow row = (GridViewRow)GridView.Rows[e.RowIndex];
        Label lbldeleteid = (Label)row.FindControl("lblID");
        con.Open();
        SqlCommand cmd = new SqlCommand("delete FROM detail where id='" + Convert.ToInt32(GridView.DataKeys[e.RowIndex].Value.ToString()) + "'", con);
        cmd.ExecuteNonQuery();
        con.Close();
        BindGrid();
    }

    protected void GridView_RowUpdating(object sender, GridViewUpdateEventArgs e)
    {
        SqlConnection con = new SqlConnection(connectionString);

        int Config_id = Convert.ToInt32(GridView.DataKeys[e.RowIndex].Value.ToString());
        GridViewRow row = (GridViewRow)GridView.Rows[e.RowIndex];
        Label lblID = (Label)row.FindControl("lblID");
        //TextBox txtname=(TextBox)gr.cell[].control[];  
        TextBox group = (TextBox)row.Cells[0].Controls[0];
        TextBox key = (TextBox)row.Cells[1].Controls[0];
        TextBox label = (TextBox)row.Cells[2].Controls[0];
        //TextBox textadd = (TextBox)row.FindControl("txtadd");  
        //TextBox textc = (TextBox)row.FindControl("txtc");  
        GridView.EditIndex = -1;
        con.Open();
        //SqlCommand cmd = new SqlCommand("SELECT * FROM detail", conn);  
        SqlCommand cmd = new SqlCommand("update detail set group='" + group.Text + "',key='" + key.Text + "',label ='" + label.Text + "'where id='" + Config_id + "'", con);
        cmd.ExecuteNonQuery();
        con.Close();
        BindGrid();
        //GridView1.DataBind(); 
    }

    protected void GridView_RowCancelingEdit(object sender, GridViewCancelEditEventArgs e)
    {
        GridView.EditIndex = -1;
        BindGrid();
    }