以下是想更新gridview的内容的代码,点“编辑”后,在文本框无论输什么内容,点“更新”按键  ,数据库内容依然没变,为什么啊??protected void GridView1_RowUpdating(object sender, GridViewUpdateEventArgs e)
    {
        int uid = Convert.ToInt32(GridView1.DataKeys[e.RowIndex].Value.ToString());
        //Response.Write(uid);
        string teststr = ((TextBox)(GridView1.Rows[e.RowIndex].Cells[2].Controls[0])).Text.ToString();
        //Response.Write(teststr);
        string sqlstr2 = "update test set username='" + teststr + "' where id=" + uid;
        //Response.Write(sqlstr2);          
        SqlConnection sqlcon2 = getcon();
        sqlcon2.Open();
        SqlCommand mycm2 = new SqlCommand(sqlstr2,sqlcon2);
        mycm2.ExecuteNonQuery();
        mycm2.Dispose();
        sqlcon2.Close();
        GridView1.EditIndex = -1;
        this.DataBind();
    }