When I set the DropDownList.SelectedIndex of ONE DropDownList they ALL change!

  • Thread starter Thread starter S_K
  • Start date Start date
S

S_K

Hi,

I have a list of 6 DropDownList boxes, from DropDownList1 to
DropDownList6, and I'm changing the SelectedIndex of each using a
foreach loop as follows:

foreach(PaymentReqDisplay thispayment in listPaymentReqDisplay)
{
if ((string)thispayment.TaxType == "FIT")
this.DropDownList1.SelectedIndex =
(int)thispayment.PaymentRequirementID - 1;
if ((string)thispayment.TaxType == "FUI")
this.DropDownList2.SelectedIndex =
(int)thispayment.PaymentRequirementID - 1;
if ((string)thispayment.TaxType == "SIT")
this.DropDownList3.SelectedIndex =
(int)thispayment.PaymentRequirementID - 1;
if ((string)thispayment.TaxType == "SUI")
this.DropDownList4.SelectedIndex =
(int)thispayment.PaymentRequirementID - 1;
if ((string)thispayment.TaxType == "ETF")
this.DropDownList5.SelectedIndex =
(int)thispayment.PaymentRequirementID - 1;
if ((string)thispayment.TaxType == "SDI")
this.DropDownList6.SelectedIndex =
(int)thispayment.PaymentRequirementID - 1;
}

The problem is that when I change, say, DropDownList4.SelectedIndex =
3; every other DropDownList's SelectedIndex changes as well!?

What am I doing wrong?

Thanks much for your help.
Steve
 
Do all ddls share the same items?

When you set the SelectedIndex property, it actually sets the Selected
property of the item you select. Thus the same item becomes selected in all
ddls it is participating.

The solution is to replicate the item collection for every single ddl.

--
Eliyahu Goldin,
Software Developer
Microsoft MVP [ASP.NET]
http://msmvps.com/blogs/egoldin
http://usableasp.net
 
Do all ddls share the same items?

When you set the SelectedIndex property, it actually sets the Selected
property of the item you select. Thus the same item becomes selected in all
ddls it is participating.

The solution is to replicate the item collection for every single ddl.

--
Eliyahu Goldin,
Software Developer
Microsoft MVP [ASP.NET]http://msmvps.com/blogs/egoldinhttp://usableasp.net




Hi,
Click to expand...
I have a list of 6 DropDownList boxes, from DropDownList1 to
DropDownList6, and I'm changing the SelectedIndex of each using a
foreach loop as follows:
Click to expand...
foreach(PaymentReqDisplay thispayment in listPaymentReqDisplay)
{
if ((string)thispayment.TaxType == "FIT")
this.DropDownList1.SelectedIndex =
(int)thispayment.PaymentRequirementID - 1;
if ((string)thispayment.TaxType == "FUI")
this.DropDownList2.SelectedIndex =
(int)thispayment.PaymentRequirementID - 1;
if ((string)thispayment.TaxType == "SIT")
this.DropDownList3.SelectedIndex =
(int)thispayment.PaymentRequirementID - 1;
if ((string)thispayment.TaxType == "SUI")
this.DropDownList4.SelectedIndex =
(int)thispayment.PaymentRequirementID - 1;
if ((string)thispayment.TaxType == "ETF")
this.DropDownList5.SelectedIndex =
(int)thispayment.PaymentRequirementID - 1;
if ((string)thispayment.TaxType == "SDI")
this.DropDownList6.SelectedIndex =
(int)thispayment.PaymentRequirementID - 1;
}
Click to expand...
The problem is that when I change, say, DropDownList4.SelectedIndex =
3; every other DropDownList's SelectedIndex changes as well!?
Click to expand...
What am I doing wrong?
Click to expand...
Thanks much for your help.
Steve- Hide quoted text -
Click to expand...

- Show quoted text -
Click to expand...

So you are saying that by setting the SelectIndex of (say) the first
ddl ALL of the ddls in that group get set along with it?
So how do I replicate the item collection for every single ddl? I
don't understand what you mean. Could you give me a code example?

Thanks so much for your help.
Steve
 
I mean every ddl should have it's own item collection, not shared with the
other ddls.

How do you populate the ddls?

--
Eliyahu Goldin,
Software Developer
Microsoft MVP [ASP.NET]
http://msmvps.com/blogs/egoldin
http://usableasp.net


S_K said:
Do all ddls share the same items?

When you set the SelectedIndex property, it actually sets the Selected
property of the item you select. Thus the same item becomes selected in
all
ddls it is participating.

The solution is to replicate the item collection for every single ddl.

--
Eliyahu Goldin,
Software Developer
Microsoft MVP
[ASP.NET]http://msmvps.com/blogs/egoldinhttp://usableasp.net




Hi,
Click to expand...
I have a list of 6 DropDownList boxes, from DropDownList1 to
DropDownList6, and I'm changing the SelectedIndex of each using a
foreach loop as follows:
Click to expand...
foreach(PaymentReqDisplay thispayment in listPaymentReqDisplay)
{
if ((string)thispayment.TaxType == "FIT")
this.DropDownList1.SelectedIndex =
(int)thispayment.PaymentRequirementID - 1;
if ((string)thispayment.TaxType == "FUI")
this.DropDownList2.SelectedIndex =
(int)thispayment.PaymentRequirementID - 1;
if ((string)thispayment.TaxType == "SIT")
this.DropDownList3.SelectedIndex =
(int)thispayment.PaymentRequirementID - 1;
if ((string)thispayment.TaxType == "SUI")
this.DropDownList4.SelectedIndex =
(int)thispayment.PaymentRequirementID - 1;
if ((string)thispayment.TaxType == "ETF")
this.DropDownList5.SelectedIndex =
(int)thispayment.PaymentRequirementID - 1;
if ((string)thispayment.TaxType == "SDI")
this.DropDownList6.SelectedIndex =
(int)thispayment.PaymentRequirementID - 1;
}
Click to expand...
The problem is that when I change, say, DropDownList4.SelectedIndex =
3; every other DropDownList's SelectedIndex changes as well!?
Click to expand...
What am I doing wrong?
Click to expand...
Thanks much for your help.
Steve- Hide quoted text -
Click to expand...

- Show quoted text -
Click to expand...

So you are saying that by setting the SelectIndex of (say) the first
ddl ALL of the ddls in that group get set along with it?
So how do I replicate the item collection for every single ddl? I
don't understand what you mean. Could you give me a code example?

Thanks so much for your help.
Steve
Click to expand...
 
So you are saying that by setting the SelectIndex of (say) the first
ddl ALL of the ddls in that group get set along with it?
So how do I replicate the item collection for every single ddl? I
don't understand what you mean. Could you give me a code example?

Thanks so much for your help.
Steve- Hide quoted text -

- Show quoted text -
Click to expand...

I FOUND THE PROBLEM!!!

This is what happend.
In my code I called a method to fill the Items value for each
DropDownList using a ListItem as in the code:

for (int i = 0; i < listPaymentReq.Count; i++)
{
ListItem li = new
ListItem(listPaymentReq.Payment_Req_Code.ToString(),
listPaymentReq.Payment_Req_ID.ToString());

DropDownList1.Items.Insert(i, li);
DropDownList2.Items.Insert(i, li);
DropDownList3.Items.Insert(i, li);
..
..
.. }

Note that the "li" is a pointer and I'm inserting the SAME Items value
into each ddl! This apparently means that the SelectedIndex for each
ddl is also a pointer pointing to the same location as well.

You learn something new everyday.

thanks for the help.

Steve
 
This apparently means that the SelectedIndex for each
ddl is also a pointer pointing to the same location as well.
Click to expand...

SelectedIndex is not a pointer, it is a property and when you set or get it,
some code runs.

When you "set" it, asp.net goes to the Items collection and mark the item as
"Selected" be setting li.Selected = true.

When you "get" the SelectedIndex on another ddl, asp.net goes to the Items
collection, finds the item with Selected=true and returns it's index. This
causes the effect you observed and successfully fixed.

--
Eliyahu Goldin,
Software Developer
Microsoft MVP [ASP.NET]
http://msmvps.com/blogs/egoldin
http://usableasp.net


S_K said:
Do all ddls share the same items?
Click to expand...
When you set the SelectedIndex property, it actually sets the Selected
property of the item you select. Thus the same item becomes selected
in all
ddls it is participating.
Click to expand...
The solution is to replicate the item collection for every single ddl.
Click to expand...
--
Eliyahu Goldin,
Software Developer
Microsoft MVP
[ASP.NET]http://msmvps.com/blogs/egoldinhttp://usableasp.net
Click to expand...
I have a list of 6 DropDownList boxes, from DropDownList1 to
DropDownList6, and I'm changing the SelectedIndex of each using a
foreach loop as follows:
Click to expand...
foreach(PaymentReqDisplay thispayment in listPaymentReqDisplay)
{
if ((string)thispayment.TaxType == "FIT")
this.DropDownList1.SelectedIndex =
(int)thispayment.PaymentRequirementID - 1;
if ((string)thispayment.TaxType == "FUI")
this.DropDownList2.SelectedIndex =
(int)thispayment.PaymentRequirementID - 1;
if ((string)thispayment.TaxType == "SIT")
this.DropDownList3.SelectedIndex =
(int)thispayment.PaymentRequirementID - 1;
if ((string)thispayment.TaxType == "SUI")
this.DropDownList4.SelectedIndex =
(int)thispayment.PaymentRequirementID - 1;
if ((string)thispayment.TaxType == "ETF")
this.DropDownList5.SelectedIndex =
(int)thispayment.PaymentRequirementID - 1;
if ((string)thispayment.TaxType == "SDI")
this.DropDownList6.SelectedIndex =
(int)thispayment.PaymentRequirementID - 1;
}
Click to expand...
The problem is that when I change, say, DropDownList4.SelectedIndex =
3; every other DropDownList's SelectedIndex changes as well!?
Click to expand...
What am I doing wrong?
Click to expand...
Thanks much for your help.
Steve- Hide quoted text -
Click to expand...
- Show quoted text -
Click to expand...

So you are saying that by setting the SelectIndex of (say) the first
ddl ALL of the ddls in that group get set along with it?
So how do I replicate the item collection for every single ddl? I
don't understand what you mean. Could you give me a code example?

Thanks so much for your help.
Steve- Hide quoted text -

- Show quoted text -
Click to expand...

I FOUND THE PROBLEM!!!

This is what happend.
In my code I called a method to fill the Items value for each
DropDownList using a ListItem as in the code:

for (int i = 0; i < listPaymentReq.Count; i++)
{
ListItem li = new
ListItem(listPaymentReq.Payment_Req_Code.ToString(),
listPaymentReq.Payment_Req_ID.ToString());

DropDownList1.Items.Insert(i, li);
DropDownList2.Items.Insert(i, li);
DropDownList3.Items.Insert(i, li);
.
.
. }

Note that the "li" is a pointer and I'm inserting the SAME Items value
into each ddl! This apparently means that the SelectedIndex for each
ddl is also a pointer pointing to the same location as well.

You learn something new everyday.

thanks for the help.

Steve
Click to expand...
 
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