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How to insert multiple different textboxes to database table one by one for each row?

I have 3 different textboxes for serials. And when I click the button I want to save them for each row in database table.
Textbox1.Text="HP" ==> STOCKID
Textbox2.Text="İ5" ==> MODEL
Textbox3.Text="3" ==> QUANTITY
Textbox4.Text="11231231"; ==> SERIAL-1
Textbox5.Text="11231231"; ==> SERIAL-2
Textbox6.Text="11231231"; ==> SERIAL-2
Then Button click event.
Result should be as below.
FIRST GRIDVIEW
STOKID
MODEL
QUANTİTY
HP
I5
3
SECOND GRIDVIEW
STOKID
MODEL
SERIALS
DELETEBUTTON
HP
I5
32165161
BUTTON
HP
I5
12313223
BUTTON
HP
I5
16516516
BUTTON
When I delete from serials one bye one, the first Gridview QTY should decrease one for each serials. Is it possible?
I use store procedure during insert to data for first gridview. But for second one I don't know how to use a loop for textboxes and add to database different serials(textboxes values).

Ok, so say this markup:
We have Stokkid, model, and then have 3 optional serial num boxes
(if they are left blank - we don't add).
So, this markup:
The boxes, and add button:
<div style="float: left">
<h4>Stokid</h4>
<asp:TextBox ID="txtStokID" runat="server"></asp:TextBox>
</div>
<div style="float: left;margin-left:20px">
<h4>Model</h4>
<asp:TextBox ID="txtModel" runat="server"></asp:TextBox>
</div>
<div style="float: left;margin-left:20px">
<h4>Serial 1</h4>
<asp:TextBox ID="txtS1" runat="server"></asp:TextBox>
</div>
<div style="float: left;margin-left:20px">
<h4>Serial 2</h4>
<asp:TextBox ID="txtS2" runat="server"></asp:TextBox>
</div>
<div style="float: left;margin-left:20px">
<h4>Serial 3</h4>
<asp:TextBox ID="txtS3" runat="server"></asp:TextBox>
</div>
<div style="float: left;margin-left:20px;margin-top:20px">
<asp:Button ID="cmdSave" runat="server" Text="Save/Add" CssClass="btn"
OnClick="cmdSave_Click"
/>
</div>
<div style="clear:both" ></div>
And right below that, 2 grids, the first totals gv, and then the data we have gv.
So, this:
<h3>Counts</h3>
<asp:GridView ID="GVCounts" runat="server" CssClass="table"
width="40%" ShowHeaderWhenEmpty="True" >
</asp:GridView>
<h3>Items</h3>
<asp:GridView ID="GridView1" runat="server" CssClass="table"
width="40%" ShowHeaderWhenEmpty="True" >
</asp:GridView>
And now our code to load up the above:
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
LoadData();
}
void LoadData()
{
// load up "counts" grid
string strSQL =
#"SELECT Stokid, Model, count(*) as QTY FROM tblSerials
GROUP BY Stokid, Model";
GVCounts.DataSource = MyRst(strSQL);
GVCounts.DataBind();
// Load up existing data grid
strSQL =
#"SELECT Stokid, Model, Serials FROM tblSerials ORDER BY ID";
GridView1.DataSource = MyRst(strSQL);
GridView1.DataBind();
}
So, only part left is the "add new data button"
That code is this:
protected void cmdSave_Click(object sender, EventArgs e)
{
// save (add) one row for each serial number,
// if no serial - then don't add
DataTable dt = MyRst("SELECT * FROM tblSerials WHERE ID = 0");
DataRow MyAddRow = dt.NewRow();
MyAddRow["Stokid"] = txtStokID.Text;
MyAddRow["Model"] = txtModel.Text;
MyAddRow["Serials"] = txtS1.Text;
dt.Rows.Add(MyAddRow);
if (txtS2.Text != "")
{
MyAddRow = dt.NewRow();
MyAddRow["Stokid"] = txtStokID.Text;
MyAddRow["Model"] = txtModel.Text;
MyAddRow["Serials"] = txtS2.Text;
dt.Rows.Add(MyAddRow);
}
if (txtS3.Text != "")
{
MyAddRow = dt.NewRow();
MyAddRow["Stokid"] = txtStokID.Text;
MyAddRow["Model"] = txtModel.Text;
MyAddRow["Serials"] = txtS3.Text;
dt.Rows.Add(MyAddRow);
}
// send/save all rows to database
using (SqlConnection conn = new SqlConnection(Properties.Settings.Default.TEST5))
{
using (SqlCommand cmdSQL = new SqlCommand("SELECT * FROM tblSerials", conn))
{
conn.Open();
SqlDataAdapter da = new SqlDataAdapter(cmdSQL);
SqlCommandBuilder daU = new SqlCommandBuilder(da);
da.Update(dt);
}
}
// Update counts and display
LoadData();
}
so, the result is now this:
Now, we do probably want to setup a delete button.
so, that means our "cheat" life and easy GV of data?
Well, we have to give it a bit more effort, love and care.
We need the database PK id, and we want that delete button.
And since the delete button can be a danger, then it should confirm.
So, we have to update our GV a bit, bite the bullet and use some templating. but, it is not much.
And lets use a boot-strap icon - they should be part of any most recent project by defualt. But BE warned, after boottrap 4, the later versions (due to some copyright/lawsuit, bootstrap does not include the glyph-icons).
Anyway, I COULD use a plain jane asp.net button in the gv for delete, but lets use standard html button - I ONLY use the html one, since I wanted the cute icon. Probably better for you to use a image button.
(code is much the same either way).
So, our 2nd gv now looks like this:
<h3>Items</h3>
<asp:GridView ID="GridView1" runat="server" CssClass="table table-hover"
width="40%" ShowHeaderWhenEmpty="True" DataKeyNames="ID"
AutoGenerateColumns="False" >
<Columns>
<asp:BoundField DataField="STOKID" HeaderText="STOKID" />
<asp:BoundField DataField="MODEL" HeaderText="MODEL" />
<asp:BoundField DataField="serials" HeaderText="serials" />
<asp:TemplateField HeaderText="Delete" ItemStyle-Width="80px" ItemStyle-HorizontalAlign="Center">
<ItemTemplate>
<button id="cmdDelete" runat="server" class="btn"
onclick="if (!confirm('Delete')) return false;"
onserverclick="cmdDel_ServerClick" >
<span aria-hidden="true" class="glyphicon glyphicon-trash"></span>
</button>
</ItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>
And the code to load up this gv is now:
void LoadData()
{
// load up "counts" grid
string strSQL =
#"SELECT Stokid, Model, count(*) as QTY FROM tblSerials
GROUP BY Stokid, Model";
GVCounts.DataSource = MyRst(strSQL);
GVCounts.DataBind();
// Load up existing data grid
strSQL = #"SELECT * FROM tblSerials ORDER BY ID";
GridView1.DataSource = MyRst(strSQL);
GridView1.DataBind();
}
And our delete code is this:
protected void cmdDel_ServerClick(object sender, EventArgs e)
{
HtmlButton btn = (HtmlButton)sender;
GridViewRow gRow = (GridViewRow)btn.NamingContainer;
int PKID = (int)GridView1.DataKeys[gRow.RowIndex]["ID"];
string strSQL = "DELETE FROM tblSerial WHERE ID = {PKID}";
using (SqlConnection conn = new SqlConnection(Properties.Settings.Default.TEST5))
{
using (SqlCommand cmdSQL = new SqlCommand(strSQL, conn))
{
conn.Open();
cmdSQL.ExecuteNonQuery();
}
}
// update count and items gv
LoadData();
}
So, now we see, get this for a delete:
Edit2: The Myrst routine
In a few places in above, I also used this helper routine, since I get VERY tired VERY fast having to write code each and every time I want some data, so, I wrote and use this routine:
DataTable MyRst(string strSQL)
{
DataTable rstData = new DataTable();
using (SqlConnection conn = new SqlConnection(Properties.Settings.Default.TEST5))
{
using (SqlCommand cmdSQL = new SqlCommand(strSQL, conn))
{
conn.Open();
rstData.Load(cmdSQL.ExecuteReader());
}
}
return rstData;
}
It handy for filling out a gridview, dropdown list etc.

Add new data to gridview without refreshing entire gridview

I know the title might make my question look like a duplicate so please read the complete question first.
I have 3 dropdowns in my webform and based on those parameters the data is retrieved from the database and my gridview is populated. What I need is that once a result is displayed, if the user changes the parameters, the new retrieved data should be displayed below the old data. But currently my gridview is refreshing entirely and only the data based on new parameters is displayed.
I have read that one way is to use viewstate but I dont understand what it is. Can someone please help? Thank you.

Ok, so this is a difficult question. It is rather easy to filter, and have a cumulative filter.
So, say we have this screen:
And lots more rows.
So, I can say lets filter by a city.
So this:
Note how we do allow multiple city in the multi-select drop down.
So, I now have this:
Now, lets select those ONLY with a description.
So this:
And then say only active ones. So, this:
So, above is quite easy to setup. Note how any option NOT selected is left out of the critera.
but, a BIG problem exists in the above.
What happens if I want Active from say B.C. but NOT active from Alberta???
I can't do that, and hence your problem.
What we could do however is add a button to above to SAVE the resulting filter, and put the "list" of filters say into a list box or collection.
we then have a search button to search on our collection of filters.
Let me see if this can work - I'll add to above a "box" or collection of each filter.
I would think a union query with distinct row for each filter would do the trick.
So, above example is not too hard - a "cumulative" filter. In fact, the code patter for 2 or 15 filters is quite easy to do here.
However, adding up separate filter requests and combine them? That is somewhat difficult to do.
Edit: Multiple filters
so, while in above, I could say filter by city and get all active, but THEN I want to filter by another city, and get all NON active!!!
That's the problem here.
So, we would have to add code to SAVE the filter. And the HUGE problem with that is how then do we save each filter to "add up" each filter set we want?
We could try and save the raw SQL, but such SQL would be subject to sql injection, and we want to always use parameters.
So, we can and could adopt a design in which we SAVE the resulting SqlCommand object. And then merge the results.
So, now our UI becomes like this:
Lets grab and filter all those from city Edmonton, but Active,
so, this:
We now hit save filter and this:
And now we filter by say City = Banff, but don't care about active or not.
So we have this:
We then save that filter - and now we have this:
I now hit the filter button below the list of filters, and we get this:
So, how does this code work?
Well, I simple saved the Sqlcommand object to a collection (list), and thus combine the results.
So, first our markup at the top for the filter stuff.
<h4>Filters</h4>
<div style="float:left">
<asp:Label ID="Label1" runat="server" Text="Search Hotel"></asp:Label>
<br />
<asp:TextBox ID="txtHotel" runat="server"></asp:TextBox>
</div>
<div style="float:left;margin-left:20px">
<asp:Label ID="Label2" runat="server" Text="Search City"></asp:Label>
<br />
<asp:TextBox ID="txtCity" runat="server"></asp:TextBox>
</div>
<div style="float:left;margin-left:20px">
<asp:Label ID="Label3" runat="server" Text="Must Have Description"></asp:Label>
<br />
<asp:CheckBox ID="chkDescripiton" runat="server" />
</div>
<div style="float:left;margin-left:20px">
<asp:Label ID="Label4" runat="server" Text="Show only Active Hotels"></asp:Label>
<br />
<asp:CheckBox ID="chkActiveOnly" runat="server" />
</div>
<div style="float:left;margin-left:20px">
<asp:Button ID="cmdSearch" runat="server" Text="Search" CssClass="btn" OnClick="cmdSearch_Click"/>
</div>
<div style="float:left;margin-left:20px">
<asp:Button ID="cmdClear" runat="server" Text="Clear Fitler" CssClass="btn" OnClick="cmdClear_Click"/>
</div>
<div style="float:left;margin-left:20px">
<asp:Button ID="cmdTest" runat="server" Text="Save Filter"
CssClass="btn" OnClick="cmdTest_Click"
OnClientClick="return myfilterprompt()"
/>
<asp:HiddenField ID="HFilterName" runat="server" ClientIDMode="Static"/>
<script>
function myfilterprompt() {
sFilter = ""
sFilter = prompt('Enter name for filter ')
if ( (sFilter === null) || (sFilter === "") ){
return false
}
$('#HFilterName').val(sFilter)
return true
}
</script>
</div>
<div style="float:left;margin-left:30px;width:190px">
<asp:ListBox ID="lstFilters" runat="server" Width="100%" Height="100px"
DataTextField="sFilterName" >
</asp:ListBox>
<asp:Button ID="cmdMultiFilter" runat="server" Text="Filter"
CssClass="btn" OnClick="cmdMultiFilter_Click" style="float:left" />
<asp:Button ID="cmdMultiClear" runat="server" Text="Clear"
CssClass="btn" OnClick="cmdMultiClear_Click" style="float:right"/>
</div>
then below above is our grid:
<asp:GridView ID="GridView1" runat="server"
AutoGenerateColumns="False" DataKeyNames="ID"
CssClass="table" Width="60%" ShowHeaderWhenEmpty="true">
<Columns>
<asp:BoundField DataField="FirstName" HeaderText="FirstName" />
<asp:BoundField DataField="LastName" HeaderText="LastName" />
<asp:BoundField DataField="HotelName" HeaderText="HotelName" />
<asp:BoundField DataField="City" HeaderText="City" />
<asp:BoundField DataField="Province" HeaderText="Province" />
<asp:BoundField DataField="Description" HeaderText="Description" />
<asp:BoundField DataField="Active" HeaderText="Active" />
</Columns>
</asp:GridView>
So, code to load:
List<MyFilter> MyFilters = new List<MyFilter>();
protected void Page_Load(object sender, EventArgs e)
{
if (IsPostBack == false)
{
SqlCommand cmdSQL = new
SqlCommand("SELECT * FROM tblHotels WHERE ID = 0");
LoadGrid(cmdSQL);
Session["MyFilters"] = MyFilters;
}
else
MyFilters = (List<MyFilter>)Session["MyFilters"];
}
public void LoadGrid(SqlCommand cmdSQL)
{
DataTable rstData = MyRstP(cmdSQL);
GridView1.DataSource = rstData;
GridView1.DataBind();
}
And now our search button:
protected void cmdSearch_Click(object sender, EventArgs e)
{
SqlCommand cmdSQL = GetMyCommand();
LoadGrid(cmdSQL);
}
SqlCommand GetMyCommand()
{
string strSQL = "SELECT * FROM tblHotels ";
string strORDER = " ORDER BY HotelName";
string strFilter = "";
SqlCommand cmdSQL = new SqlCommand();
if (txtHotel.Text != "")
{
strFilter = "(HotelName like #HotelName + '%')";
cmdSQL.Parameters.Add("#HotelName", SqlDbType.NVarChar).Value = txtHotel.Text;
}
if (txtCity.Text != "")
{
if (strFilter != "") strFilter += " AND ";
strFilter += "(City Like #City + '%') ";
cmdSQL.Parameters.Add("#City", SqlDbType.NVarChar).Value = txtCity.Text;
}
if (chkActiveOnly.Checked)
{
if (strFilter != "") strFilter += " AND ";
strFilter += "(Active = 1)";
}
if (chkDescripiton.Checked)
{
if (strFilter != "") strFilter += " AND ";
strFilter += "(Description is not null)";
}
if (strFilter != "") strSQL += " WHERE " + strFilter;
strSQL += strORDER;
cmdSQL.CommandText = strSQL;
return cmdSQL;
}
And now our save the filter button code:
protected void cmdTest_Click(object sender, EventArgs e)
{
MyFilter OneFilter = new MyFilter();
OneFilter.sFilterName = HFilterName.Value;
OneFilter.cmdSQL = GetMyCommand();
MyFilters.Add(OneFilter);
lstFilters.DataSource = MyFilters;
lstFilters.DataBind();
}
public class MyFilter
{
public string sFilterName { get; set; }
public SqlCommand cmdSQL = new SqlCommand();
}
And our multi-filter code button.
Now, for large data sets - not a great idea, but a start:
protected void cmdMultiFilter_Click(object sender, EventArgs e)
{
List<DataTable> MyTables = new List<DataTable>();
foreach (MyFilter OneFilter in MyFilters)
{
DataTable rstDT = MyRstP(OneFilter.cmdSQL);
MyTables.Add(rstDT);
}
DataTable rstData = MyTables[0];
for (int i = 1;i < MyTables.Count;i++)
{
rstData.Merge(MyTables[i]);
}
GridView1.DataSource = rstData;
GridView1.DataBind();
}
so, you can build list up of "filters" and display them in a listbox and then have a filter button that merges all of the filtering.
And one more helper routine I used:
public DataTable MyRstP(SqlCommand cmdSQL)
{
DataTable rstData = new DataTable();
using (SqlConnection conn = new SqlConnection(Properties.Settings.Default.TEST4))
{
using (cmdSQL)
{
cmdSQL.Connection = conn;
conn.Open();
rstData.Load(cmdSQL.ExecuteReader());
}
}
return rstData;
}
These systems can be really nice. Often a group of managers will say, lets grab all customers from west coast. Yuk - too many. Ok, only those with purchases in last 2 months - ah, that's nice.
then they say, lets get all customers who never purchased anything, but from the south - and add those to the list - but only active on our mailing list.
So, this type of slice and dice - get some of those, and then get some of these, and then combine them?
This type of business query system and being able to combine these, and those, and them, and then toss in a few more? Often they will keep going say until such time they get say 10,000 results (which happens to be how many catalogs they have left they would like to send out).

So, I solved my problem by using a little outside the box thinking. I am posting it here for anyone visiting this question or having a same problem in the future could see this:
So what I did is that I extracted the data from the database based on the parameters selected by the user from the dropdowns. In the database, I had created a temp table to store the extracted temporarily. So I inserted the data into that temporary table and used that table to populate the gridview. I had to add a reset button, when the user clicked it the all the data is deleted from the temp table and also the page reset to its default with gridview not visible and dropdowns having no selection.

Code Not Preventing Duplicate E-mail Addresses in Database

The code I have is allowing duplicate e-mails to be added to the database. I added a line of code before allowing entry into the database to prevent duplicate e-mail addresses to be added, however with this code I am still getting duplicate e-mails. I have provided both the form code in asp.net & the c# code. Please help.
Originally I was getting an error & I debugged the code in VS & realized that I actually had the wrong specification for the email entry, that has been corrected. In the VS debugger I see values for TextBox1.Text & TextBox2.Text, i also see the e-mail address passing through the string query = the issue however is that even if the e-mail is already in the database, it still gets added again. Any improvements to fix this issue with my code? Is my logic wrong perhaps?
c# code:
protected void Button1_Click(object sender, EventArgs e)
{
OleDbConnection con = new OleDbConnection();
con.ConnectionString = ConfigurationManager.ConnectionStrings["northwind"].ToString();
con.Open();
string query = "SELECT COUNT(ID) FROM Table1 WHERE pEmail= '" + TextBox2.Text +"'";
OleDbCommand cmd = new OleDbCommand(query, con);
var count = cmd.ExecuteNonQuery();
if (count > 0)
{
Label1.Text = "email is already in use";
}
else {
cmd.CommandText = "insert into[Table1](pName, pEmail)values(#nm,#em)";
cmd.Parameters.AddWithValue("#nm", TextBox1.Text);
cmd.Parameters.AddWithValue("#em", TextBox2.Text);
cmd.Connection = con;
int a = cmd.ExecuteNonQuery();
if (a>0)
{
Label1.Text = "Inserted Sucessfully!";
}
}
}
}
Form Code:
<form id="form1" runat="server">
<div style="height: 138px">
Enter Name:<asp:TextBox ID="TextBox1" runat="server" style="margin-left: 12px"></asp:TextBox>
<asp:RequiredFieldValidator
id="reqName"
ControlToValidate="TextBox1"
Style="color:Red"
ErrorMessage="Please enter your name!"
runat="server" />
<br />
Enter Email:
<asp:TextBox ID="TextBox2" runat="server"></asp:TextBox>
<asp:RegularExpressionValidator
id="ValidEmail"
ControlToValidate="TextBox2"
Style="color:Red"
ValidationExpression="^([a-zA-Z0-9_\-\.]+)#((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.)|(([a-zA-Z0-9\-]+\.)+))([a-zA-Z]{2,4}|[0-9]{1,3})(\]?)$"
ErrorMessage="Invalid Email Entry"
runat="server" />
<br />
<asp:Button ID="Button1" runat="server" OnClick="Button1_Click" Text="Submit" />
<br />
<asp:Label ID="Label1" runat="server"></asp:Label>
</div>
</form>

You should use ExecuteScalar instead of ExecuteNonQuery to get the row count
Original:
var count = cmd.ExecuteNonQuery();
Suggest to change:
var count = cmd.ExecuteScalar();
Refer to https://stackoverflow.com/a/4269651/1050927
The ExecuteNonQuery Method returns the number of row(s) affected by either an INSERT, an UPDATE or a DELETE. This method is to be used to perform DML (data manipulation language) statements as stated previously.
The ExecuteScalar Method will return a single value in the first row, first column from a SELECT statement. This method is to be used when you expect only one value from the query to be returned.

Use ExecuteScalar and Convert the result to int. I also recommend you to change the sql query concatenation to parameters, and if you are using ASP.NET Validators, you must check the property IsValid of the page as it will tell you if the controls has passed validation (remember that users can disable javascript and post the form).
protected void Button1_Click(object sender, EventArgs e)
{
if (IsValid)
{
using (var con = new OleDbConnection())
{
con.ConnectionString = ConfigurationManager.ConnectionStrings["northwind"].ToString();
con.Open();
using (var cmd = con.CreateCommand())
{
cmd.CommandText = "SELECT COUNT(ID) FROM Table1 WHERE pEmail= #em";
cmd.Parameters.AddWithValue("#em", TextBox2.Text);
int count = Convert.ToInt32(cmd.ExecutScalar());
if (count > 0)
{
Label1.Text = "email is already in use";
}
else
{
cmd.CommandText = "insert into[Table1](pName, pEmail)values(#nm, #em)";
cmd.Parameters.AddWithValue("#nm", TextBox1.Text);
// not need to add #em parameter, it was added previously
int insertedRows = cmd.ExecuteNonQuery();
if (insertedRows > 0)
{
Label1.Text = "Inserted Sucessfully!";
}
}
}
}
}
}

Getting textbox.text in gridview auto generated edit control

Hi i am having a problem using the auto generated edit button in my gridview.
i am trying to get the username from the edit text box and insert it to my database like so:
<asp:TemplateField HeaderText="User Name">
<ItemTemplate>
<asp:Label ID="UserNamelbl" runat="server" Text='<%# Eval("Username") %>'></asp:Label>
</ItemTemplate>
<EditItemTemplate>
<asp:TextBox ID="UserNameEdit" Width="100" Text='<%# Eval("Username") %>' Enabled="true" runat="server"></asp:TextBox></EditItemTemplate>
</asp:TemplateField>
c# method that occurs on the update click.
protected void UsersGridView_RowUpdating(object sender, GridViewUpdateEventArgs e)
{
GridViewRow row = UsersGridview.Rows[e.RowIndex];
Connect c = new Connect("EdenSiteDB.accdb");
string updatesql = "UPDATE Users Set Username= '" + ((TextBox)row.FindControl("UserNameEdit")).Text + "' , Email= '" + ((TextBox)row.FindControl("EmailEdit")).Text + "' , Admin= " + (((CheckBox)row.FindControl("IsAdminBoxEdit")).Checked).ToString() + " WHERE UserID= " + Session["UserId"].ToString() + ";";
OleDbCommand updatecmm = new OleDbCommand(updatesql);
c.TakeAction(updatecmm);
string usersql = "SELECT * FROM Users;";
dt = c.MakeConnection(usersql, "Users");
UsersGridview.EditIndex = -1;
DataBind();
}
While running this is the updatesql:
updatesql = "UPDATE Users Set Username= 'edmx0' , Email= 'edmx0.et#gmail.com' , Admin= True WHERE UserID= 17;"
these are the previouse values. not the new ones i just entered.
but when i debug it, my sql keeps coming up with the initial username, and not the one i just entered.
I assume it has something to do with my gridview binding at that moment but i don't know how to fix it.
Any help would be appreciated!

can you step through to a breakpoint at the OleDbCommand and post the result of
updatesql
before the update command runs?

How to retrieve text from dropdownlist?

I must audit the changes into a database. On most pages this works perfect, as there were just textboxes - however on a page I am working on right now, with dropdownlists, my code isn't working.
<td>
<asp:DropDownList ID="DropDownList4" runat="server" DataSourceID="SqlDatacountry" DataTextField="country_name" DataValueField="country_id">
</asp:DropDownList>
<asp:SqlDataSource ID="SqlDatacountry" runat="server" ConnectionString="<%$ ConnectionStrings:songtypecons %>" SelectCommand="SELECT * FROM [country_detail]"></asp:SqlDataSource>
</td>
code behind:
string sql1 = "selectcust_fname,cust_mname,cust_lname,cust_birthdate,cust_gender,cust_address,cust_contact_num,cust_country,cust_state,cust_city,cust_zip from cust_detail where cust_id ='" + ds.Tables["filldata"].Rows[0].ItemArray[0].ToString() + "' ";
SqlDataAdapter adpt1 = new SqlDataAdapter(sql1, con);
DataSet ds1 = new DataSet();
adpt1.Fill(ds1, "custdata");
if (ds1.Tables["custdata"].Rows.Count > 0)
{
for (int d = 0; d < DropDownList4.Items.Count; d++)
{
if (ds1.Tables["custdata"].Rows[0].ItemArray[7].ToString() == DropDownList4.Items[d].Text)
{
DropDownList4.Items[d].Selected = true;
break;
}
}
}

If I understand your question clearly, you just need to use your code in your ListControl.SelectedIndexChanged event.
Occurs when the selection from the list control changes between posts
to the server.
<asp:DropDownList ID="DropDownList4" runat="server" AutoPostBack="True"
onselectedindexchanged="DropDownList4_SelectedIndexChanged" ...>
</asp:DropDownList>
protected void DropDownList4_SelectedIndexChanged(object sender, EventArgs e)
{
...
}
As I wrote in my comment, you should always use parameterized queries in your sql commands, your code is open for an SQL Injection attacks.