ListBox.TopIndex unable to store 70000 as its datatype is int

Question

0.00/5 (No votes)

See more:

Current in my situation my listbox has 75000 items and on scroll i am setting the topindex value on scrolling event. But after storing more than 65536 it comes back to starting point. As ListBox.TopIndex datatype is Int so again it is setting topindex starting from zero but i need to store 70000 or 75000 in this to set the top index as my listbox contains more than 70000 items.

Is it possible to set this?

Posted 4-Dec-15 1:25am

Vikrant_Mishra

Updated 4-Dec-15 1:28am

phil.o

v2

Add a Solution

Comments

phil.o 4-Dec-15 7:39am

You may be surprised by the number of people who will refuse to use a program that presents them with 70k different items at the same time.
IMHO, you have a design issue.

Vikrant_Mishra 4-Dec-15 7:51am

yeah thats right, but this is the requirement, for that we have textbox which filter listbox with character inserted to textbox. But this situation looks bug when user scroll down the listbox it scrolls back to starting point as topindex goes off to max limit of Int Datatype.. Please help if its posible

phil.o 4-Dec-15 8:00am

The ListBox is limited to a given amount of data by design, for good reasons.
You should use filtering and paging.
And the max value of int type is far more than 65536; it is exactly 2^31 - 1 = 2,147,483,647. So the datatype of the TopIndex is not what is limiting the number of items. Implementation of ListBox is what is limiting the number of items.
If the requirement really is 'having 70k different items presented to user at the same time', then this is the requirement that is flawed.
Let me make an analogy with a car: if you had a requirement to build a (usable) car with square wheels, would it seem reasonnable to you?
Again, that much data in a single screen is insane.

CHill60 4-Dec-15 8:03am

This is so the solution! A virtual 5

Vikrant_Mishra 4-Dec-15 8:08am

ROFL, Nice example Phil. Thanks for your explanation.

phil.o 4-Dec-15 8:12am

You're welcome. Besides, it's hard to give you some links about listBox paging, since you did not tell if this is Windows Forms, or WPF, or ASP.NET,etc... that's an important information if you want meaningful answers :) Cheers.

Vikrant_Mishra 4-Dec-15 8:17am

Sorry i forgot to mention.. Its windows form.. Please help if u still can..

Alan N 4-Dec-15 11:26am

Are you able to post a concise code fragment which demonstrates the problem?

In a test with a listbox populated with 1 million integers I can set TopIndex to make the listbox scroll to any of those 1 million items. You say you are setting the TopIndex on the "scrolling" event. What do you mean by that?

1 solution

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

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

phil.o · Accepted Answer · 2015-12-04T02:53:00

I did not find any usable hint for paging a Windows Forms ListBox.
But, I found this article in on CP that deals with paging a ListView (which is not a huge change in the design):
Listview Paging in C#[^]

A 'Windows Forms ListBox paging' Google search gives some other results, too. Maybe one of them is worth browsing.

Hope this helps. Good work :)