how to update table in asp.net

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

C#

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();

                }

}
}

Posted 15-Nov-11 22:35pm

Member 7909353

Updated 15-Nov-11 22:37pm

member60

v2

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5 solutions

Solution 2

C#

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

[Edit] added pre tags

Posted 15-Nov-11 22:42pm

mibi@4289

Updated 15-Nov-11 22:55pm

v2

Solution 3

Hi,

Here is your code:

C#

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

But it should be

C#

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

Hope this helps

[Edit] added pre tags and removed superfluous line breaks

Posted 15-Nov-11 22:43pm

sriman.ch

Updated 15-Nov-11 22:56pm

v2

Solution 4

Why don't you combine your code into one sql statement

C#

// logic required to ensure it is actually an int - look up the int try parse method
st = Convert.ToInt32(TextBox1.Text);

SqlCommand cmd1 = new SqlCommand("UPDATE AddedItem SET Quantity = Quantity - " + st + " where Item_Name='" + DropDownList3.SelectedItem.Text + "'" ;

cmd1.ExecuteNonQuery();

You should also consider converting your query into a stored procedure to improve performance and prevent injection attacks

Posted 15-Nov-11 22:45pm

Reiss

Solution 5

try in the following way :

C#

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

Posted 15-Nov-11 22:57pm

member60

Updated 15-Nov-11 22:58pm

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This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

deepakdynamite · Accepted Answer · 2011-11-15T22:41:00

Solution 1

Instead of this

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

Write

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

Posted 15-Nov-11 22:41pm

deepakdynamite

Comments

ali_heidari_ 2-Oct-12 5:18am

well i did your solution but it didnt work at all ... in my application i cant use variable for update my column :s , dnt you know why i cant use variable?

deepakdynamite 5-Oct-12 0:42am

Try with casting your variable with .toString() for Eg. st1.Tostring()

how to update table in asp.net

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how to update table in asp.net

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