如何更新asp.net中的表 [英] how to update table in asp.net

问题描述

给出的代码不起作用.Table(AddedItem)未更新

Given code is not working.Table(AddedItem) is not uppdated

protected void Button1_Click(object sender, EventArgs e)
        {
            int st = 0,st1=0;
            if (IsPostBack)
            {
                try
                {
                    con.Open();
                   
                    st = Convert.ToInt32(TextBox1.Text);
                    SqlCommand cmd2 = new SqlCommand("SELECT Quantity FROM AddedItem where Item_Name='" + DropDownList3.SelectedItem.Text + "'", con);
                    SqlDataReader dr = cmd2.ExecuteReader(CommandBehavior.SingleRow);
                    if (dr.Read())
                    {

                        st1 = Convert.ToInt32(dr.GetValue(0).ToString());
                        dr.Close();
                    }
                    st1 = st1 - st;
                    SqlCommand cmd1 = new SqlCommand("UPDATE AddedItem SET Quantity=st1", con);
                    cmd1.ExecuteNonQuery();
                   
                   
                }
                catch (SqlException ex)
                {

                }
                finally
                {
                    con.Close();

                }

}
}

}
}

推荐答案

代替此

Instead of this

st1 = st1 - st;
                    SqlCommand cmd1 = new SqlCommand("UPDATE AddedItem SET Quantity=st1", con);

写

Write

st1 = st1 - st;
                    SqlCommand cmd1 = new SqlCommand("UPDATE AddedItem SET Quantity="+st1, con);

SqlCommand cmd1 = new SqlCommand("UPDATE AddedItem SET Quantity = " + st1, con);

添加了预标记

added pre tags

这是您的代码:

Hi,

Here is your code:

SqlCommand cmd1 = new SqlCommand("UPDATE AddedItem SET Quantity=st1", con);

但这应该是

But it should be

SqlCommand cmd1 = new SqlCommand("UPDATE AddedItem SET Quantity="+st1, con);

希望这会有所帮助

添加了预标签并删除了多余的换行符

Hope this helps

added pre tags and removed superfluous line breaks

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