Poplulating Text Field with DropDown selection

Hi folks. Here's a simple question. Trying to populate some text fields based on a dropdown menu selection, but it doesn't work. When a selection is made in the dropdown menu, it seems to default to the selectedValue =2. Not sure why. Any advice would be much appreciated. Thanks! Here's the code:

protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e) { TextBox1.Text =""; TextBox2.Text =""; TextBox3.Text ="";if (DropDownList1.SelectedValue =="0") TextBox1.Text ="blah";if (DropDownList1.SelectedValue =="1") TextBox1.Text ="blahblah";if (DropDownList1.SelectedValue =="2") TextBox1.Text ="blahblahblah"; }

Are you dynamicalluy populating the dropdown list in your code behind? If you are, the Page_OnLoad event is running which is populating your dropdownlist on every postback. To make sure this doesnt happen, you should populate when teh page is not posted back. in other words...

if(!Page.IsPostback){// populate my dropdownlist}

If you are not dynamically populating the dropdownlist, please make sure your viewstate is turned on, that way the server knows that index to preserve when the page is loaded again.

EnableViewState="true"

Hope this helps.

If you are adding the items to the dropdown through code in Page_Load then check if they are inside If (!Ispostback) block.

hi..

i think u can have a break point in the page load or start of selected index changed event..

and find the value..

if not..

check in the design view that item 2 isSelected=true..

correct me if i'm wrong..

Thanks to all for the suggestions. The dropDownList was statically populated from the control properties in the ASPX page. I tinkered with this for a long while, but could NOT get it to work. So, I changed approach and populated the list by making an array in the code, and now it works as designed. Thanks again. Here is the code, in case anybody is interested.

protected void Page_Load(object sender, EventArgs e) {if (!IsPostBack) {// 2 dimensional array for dropDown liststring[,] forms = { {"blah","0"}, {"blah blah","1"}, {"blah blah blah","2"} };// populate listfor (int i = 0; i < forms.GetLength(0); i++) {//add both text and value DropDownList1.Items.Add(new ListItem(forms[i, 0], forms[i, 1])); } } }protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e) {if (DropDownList1.SelectedIndex != -1) { TextBox1.Text = DropDownList1.SelectedItem.Text; } }

FYI... regarding the orginal post, the reason the textBox wasn't populated correctly was a simple syntax error. Used cascading IF statement without ELSE IF or switch statement.

Populate insert form field from GridView selection

Hi,

I'm trying to do something that seems like it should be simple, but I'm having trouble getting it to work. I have a page with a GridView and a FormView in Insert mode.

When the user selects a row in the gridview, I want to take the data keys from that selection and populate them to the appropriate textboxes in the form. I'm trying to do this in the

"GridView1_SelectedIndexChanged event" with the following code:

TextBox t;

t = (TextBox)FormView1.FindControl("myTextBox");

t.Text = (String)GridView1.SelectedDataKey.Values[0];

The text in "myTextBox" doesn't change, it remains blank. I've tried to find another event in which to put this code but so far no luck. I'm a newbie so I'm sure it's something obvious.

Can anyone help me with this? Thanks in advance.

Try moving your code to the FormView.DataBound event.

Hi Ed,

When I do that, I get "Object reference not set to an instance of an object. " I'm guessing that this is because the formview1_databound fires when the page is first loading, before there is a selected key from the gridview. I'm not sure that this is the case, it's just my best guess.

Do you have any suggestion for a workaround or alternate approach?

Thanks.

Once try this

ProtectedSub GridView1_SelectedIndexChanged(ByVal senderAsObject,ByVal eAs System.EventArgs)Handles GridView1.SelectedIndexChanged

Formview1.PageIndex = GridView1.SelectedIndex

EndSub

Hi Mahesh,

Okay, now I have this code but I still don't see the text I want populated into the text box. What am I doing wrong?

protectedvoid GridView1_SelectedIndexChanged(object sender,EventArgs e)

{

FormView1.PageIndex = GridView1.SelectedIndex;

TextBox t;

t = (TextBox)FormView1.FindControl("myTextBox");

t.Text = (String)GridView1.SelectedDataKey.Values[0];

}

How about this:

protected void GridView1_SelectedIndexChanged(object sender, EventArgs e)
{

for (int i = 0; i < GridView1.Rows.Count; i++)
{
if (GridView1.SelectedIndex == i)
{
TextBox t;

t = (TextBox)FormView1.FindControl("myTextBox");
t.Text = (String)GridView1.SelectedDataKey.Values[0];
}
}
}

Within your FormView.DataBound event, simply place a conditional statement which checks for the existence of a SelectedItem.

if (!GridView1.SelectedIndex.Equals(-1))

That did it! Thanks very much (I told you that I was a newbie :-).

Populate textbox with dropdown selection (in Wizard Control), using javascript

I have a Wizard Control that contains a number of controls:

After the user selects an item from a DropDown, and the control has lostfocus, I need the selected value to pre-populate a TextBox usingjavascript.

If I create a 'new website' and just throw a dropdown list and textbox onto the page the following code works perfectly:

** Default.aspx.vb:

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
DropDownList1.Attributes.Add("onblur", "FillTextbox()")
End Sub

** Default.aspx:

function FillTextbox ()
{
document.getElementById("TextBox1").value=document.getElementById("DropDownList1").value;
}

The above code, however DOESN'T work if the controls are embedded in a wizard control.

Thus, my question is: How do I get the code to work if the DropDown and TextBox controls are in a Wizard Control?

Any help would be much appreciated!

I believe when the control is embedded within another control the actual name that ends up being used includes the parent-control's name, e.g. Parent_mycontrol. Take a look at the source (right click, View Source) when you run the page to find the actual name of the control. You can reference it by that name in your javascript, fillTextbox() function.

Good luck.

You need to find the correct ID for the TextBox control. As suggested by the fellow developer you need to use the View Source and find the correct ID for the TextBox control. Once, you find the correct ID simply use that Id in the javascript function.

Thank you both SO MUCH for your help! That worked like a charm!

Populating a listbox from DB w/o postback

Hi,

I have 2 listboxes. The first gets populated from the db as soon as the page loads. The second listbox get populated based on the user's selection from the first listbox. However, currently the code is such that with each selection there is a postback. We want to avoid it using filter and javascript. I am not using ADO.NET but adodbc and no datagrids or datasets (please don't tell me that i should as my boss clearly doesn't want to get into it at this stage).

How can i do it?

Thanks

Currently the code with the postback is as follows:
page_load

if not page.ispostback then
Do While Not rs.EOF
li = New ListItem(rs("cat_name").Value, rs("cat_id").Value)
List1.Items.Add(li)
rs.MoveNext()
Loop

End If

'List1.SelectedIndex = 0
rs.Close()
rs = Nothing

List1.SelectedValue = cat_id

'here there is some other code not relevant to the listboxes

'select items for second listbox
Dim rsSub As New ADODB.Recordset
rsSub.Open("SELECT sub_name, sub_id FROM subs WHERE cat_id=" & cat_id.ToString & " ORDER BY sub_name ASC", cn)
Dim l_item As ListItem
Do While Not rsSub.EOF
l_item = New ListItem(rsSub("sub_name").Value, rsSub("sub_id").Value)
List2.Items.Add(l_item)
rsSub.MoveNext()
Loop

List2.SelectedValue = sub_id

rsSub.Close()
rsSub = Nothing

cn.Close()
End If
' End If

End If

End Sub

Protected Sub Select1Change(ByVal sender As System.Object, ByVal e As System.EventArgs)

Dim cn As New ADODB.Connection
cn.Open(YBayTools.Constants.ConnectionString)

Dim rs As New ADODB.Recordset
Dim li As ListItem

rs.Open("Select * from subs where cat_ID =" & List1.SelectedItem.Value.ToString, cn)
'rs.Open("Select * from subs where cat_ID ='" & List1.SelectedItem.Text.ToString & "' & List1.SelectedItem.value.ToString", cn)

Dim strCat As String

If List2.Items.Count > 0 Then
List2.Items.Clear()
End If

If rs.BOF And rs.EOF Then
Response.Write("no records found")
Else

Do While Not rs.EOF
li = New ListItem(rs("sub_name").Value, rs("sub_id").Value)
List2.Items.Add(li)
rs.MoveNext()

Loop

End If

rs.Close()
rs = Nothing
cn.Close()You code is done to work with postback. So write client-site code with javascript on the first listBox and in this code, read the DB and populate you other listBox.
That's the thing I am not sure how to write it in jscript.
I need to get the data for both listboxes from a db.
You can use an XmlHttp object from client-side script, but this will probably only work on IE and Mozilla. Other solutions could use a lot of script and hidden frames (beuark!)

Populating Dropdown List

Hi all,

I am not able to select any value from my dropdownlist,it always returns the first value. Based on the selection the corresponding record should be displayed in a text box. I have given my code here. I am totally frustrated. Pls check it out.

Page_load event
If Not Page.IsPostBack Then
sql = "select scode from supplier"
cmd = New SqlCommand(sql, con)
read = cmd.ExecuteReader
While (read.Read)
ddlscode.Items.Add(read.Item(0))
End While
ddlscode.DataBind()
End If

Private Sub ddlscode_SelectedIndexChanged(...)...
Dim sql As String
Dim i As Integer
Dim tempscode As String
con.Open()
sql = "select * from supplier "
cmd = New SqlCommand(sql, con)
adap = New SqlDataAdapter(cmd)
dt = New DataTable()
adap.Fill(dt)
For i = 0 To dt.Rows.Count - 1
If dt.Rows(i).Item("scode") = ddlscode.SelectedItem.Value Then
txtsaddr.Text = dt.Rows(i).Item("saddr")
End If
Next
read.Read()
read.Close()
con.Close()
End Subtry setting the View state of the control to true.

Set AutoPostback property equal to true.and write this code in page load

if(!page.IsPostback)

{

SqlDataReader rr;

rr=Com.ExecuteReader();

DropDownList1.DataSource=rr;

DropDownList1.DataBind();

}

Select the Value Selected value of DropdownList as

DropDownList1.SelectedItem.Text

I hope this will work but this is in c# convert into Vb

Not sure what's causing you problem, but it might be linked to your loop in the second function. A better way of handling it might be:

Private Sub ddlscode_SelectedIndexChanged(...)...
Dim sql As String
con.Open()
sql = "select saddr from supplier where scode = '" & ddlscode.SelectedItem.Value & "'"
Dim sqlComm As new System.Data.SqlClient.SqlCommand(sql,con);
txtsaddr.Text = sqlComm.ExecuteScalar()
con.Close()
End Sub

The SQL should only return 1 row (I've assumed the selected code is a text value) and the ExecuteScalar call returns the first column (in this case the 'saddr')

Hope this helps,
Nic