Hi, Im new in ASP.NET and SQL Server, i have created 1 table named detail with 3 field which is d_name, d_age, d_address

 d_name        d_age        d_country     d_gender
 iverson        32             USA                 male
 jordan         45             USA                  male

in aspx file i have 3 textbox and 1 button

txtName, txtAge, txtCountry, btnAdd 

let say if i entered the iverson in txtName then it will auto retrieve the value after the textchanged   32 (txtAge) , USA (txtCountry) then insert new record again

 Pls Help..

 Thanks 

Jordan - I'm a little confused with your question. Are you saying you want the fields to automatically update back to the database without having a user input..... lets say an update button?

not update, i want it retrieve the the data first (if the data is match from the d_name field) then insert new record again.

<asp:TextBox ID="txtName" runat="server" AutoPostBack="True" ontextchanged="txtName_TextChanged"></asp:TextBox>
<asp:TextBox ID="txtAge" runat="server"></asp:TextBox>
<asp:TextBox ID="txtCountry" runat="server" ></asp:TextBox>
<asp:Button ID="btn_add" runat="server" Text="Button" onclick="Button1_Click" />

 .cs:

protected void txtName_TextChanged(object sender, EventArgs e)
{
    using (SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["testConnectionString"].ToString()))// use your connection string here
    {
        SqlCommand cmd = new SqlCommand("select * from detail where d_name=@d_name", con);
        cmd.Parameters.AddWithValue("@d_name", txtName.Text);
        con.Open();
        SqlDataReader dr = cmd.ExecuteReader();
        if (dr != null)
        {
            while (dr.Read())
            {
                Response.Write("<script>alert('Name:" + dr["d_name"].ToString() + " already exists! \\nAge:" + dr["d_age"] + "\\nCountry:" + dr["d_country"] + " ')</script>");  
            }

        }

        // clear the textbox to insert new records.
        txtName.Text = "";
        txtAge.Text = "";
        txtCountry.Text = "";

       
    }
}

When we type a name which already exists in table “detail”,suppose “jordan”, the alert dialog will display the age and country information of “jordan”,
then the textbox controls will be cleared up to insert another new record. 

Hope this helps.

When the textchanged fired (auto postback) it will cause the error as below:

Invalid attempt to read when no data is present.

  Can i prevent this error ? , because i need the textchanged is fired whether got data or no data then insert all textbox again ?

 Thanks

Hi jordan3114,
Could you please provide your code?
Usually, this error because you don’t call the “SqlDataReader.Read()”, which advances the “SqlDataReader” to the next row.

Hi, this is my code:

protected void txtPartNo_TextChanged(object sender, EventArgs e)
        {
            string selectSQL;
            selectSQL = "SELECT * FROM part ";
            selectSQL += "WHERE part_no='" + txtPartNo.Text + "' ";
            SqlConnection con = new SqlConnection(connectionString);
            SqlCommand cmd = new SqlCommand(selectSQL, con);
            SqlDataReader reader;


                con.Open();
                reader = cmd.ExecuteReader();
                reader.Read();

                txtPartNo.Text = reader["part_no"].ToString();
                txtDesc.Text = reader["part_desc"].ToString();
                txtSize.Text = reader["part_size"].ToString();
                txtQty.Text = reader["part_quantity"].ToString();
                //txtLotNo.Text = reader["part_lot_no"].ToString();
                //txtQC.Text = reader["part_qc_accept"].ToString();
                reader.Close();
                //txtPartNo.Text = "";
                //txtDesc.Text = "";
                //txtSize.Text = "";
                lblResult.Text = "";

                con.Close();
        }

        protected void btnInsert_Click(object sender, EventArgs e)
        {
            if (txtPartNo.Text == "")
            {
                lblResult.Text = "Record require Item Part No";
                return;
            }

            string insertSQL;
            insertSQL = "INSERT INTO part( ";
            insertSQL += "part_no, part_desc, part_size, part_quantity, part_lot_no, part_qc_accept) ";
            insertSQL += "VALUES (";
            insertSQL += "@part_no, @part_desc, @part_size, @part_quantity, @part_lot_no, @part_qc_accept) ";

            SqlConnection con = new SqlConnection(connectionString);
            SqlCommand cmd = new SqlCommand(insertSQL, con);

            cmd.Parameters.AddWithValue("@part_no", txtPartNo.Text);
            cmd.Parameters.AddWithValue("@part_desc", txtDesc.Text);
            cmd.Parameters.AddWithValue("@part_size", txtSize.Text);
            cmd.Parameters.AddWithValue("@part_quantity", txtQty.Text);
            cmd.Parameters.AddWithValue("@part_lot_no", txtLotNo.Text);
            cmd.Parameters.AddWithValue("@part_qc_accept", txtQC.Text);

            int added = 0;
            try
            {
                con.Open();
                added = cmd.ExecuteNonQuery();
                lblResult.Text = added.ToString() + " Record is Added.";
            }
            catch (Exception error)
            {
                lblResult.Text = "Error Adding Record. ";
                lblResult.Text += error.Message;
            }
            finally
            {
                con.Close();
            }

            if (added > 0)
            {
                txtPartNo.Text = "";
                txtDesc.Text = "";
                txtSize.Text = "";
                txtQty.Text = "";
                txtLotNo.Text = "";
                txtQC.Text = "";
            }
        }

Hi jordan3114,
Please add an IF statement in your code and check if it works.

if(reader.Read())
{
    txtPartNo.Text = reader["part_no"].ToString();
    txtDesc.Text = reader["part_desc"].ToString();
    txtSize.Text = reader["part_size"].ToString();
    txtQty.Text = reader["part_quantity"].ToString();
    //txtLotNo.Text = reader["part_lot_no"].ToString();
    //txtQC.Text = reader["part_qc_accept"].ToString();
}

When i run textchanged it got error as below: 

Invalid object name 'part'

 at this line: reader = cmd.ExecuteReader();

Hi jordan3114,
It seems that the table named “part” cannot be found, so maybe there is something wrong with your connection string or T-SQL script, please check them.

You are right, i forgot my table is deleted , after put if (reader.Read()) it work great, My problem is solved.

Thanks a lot  Jian Kang.