This article will teach you how to get random strings for output to a label caption, or anywhere you want it to go.

1. First we need to declare our string names:

This declaration says there will be an array of strings called RndString, and there will be 2 strings in that array.

2. Then, we need to create a function that will generate a random number.

This initializes the Randomize engine, then picks a random number between the upper and lower bound values that you specify.

3. Now we need to define our strings. You'll most likely want them to be defined on form load, but if need be you may put them on a button click or something.

This defines our strings for later use.

4. Now let's say you want to change a label's caption when a user clicks a button, to one of the random strings we have previously defined. The code would look something like this:

This is where the magic happens. RndNum is used to define the index of the string array, and we set it's value equal to a random number, either 2 or 1. Then Label1's Caption becomes the string index of whatever number was produced from the randomize engine.

All done! If you need help with this code or anything else, e-mail me at ViRuaL@gmail.com

Hey thats nice! Well... I was doing it like that:
I was doing a random number, and then I was saying
If RandomNumber = 1 then
String = "Yes"
ElseIf RandomNumber = 2 then
String = "No"
End If

It's easier your way

Hey! nice code, I'm kinda new to VB, I did a little coding on my work experience in school a few months ago and I really liked it. Anyway, want I want to do is to create a program that when a button is pressed on the form, a "random" name or sentence from a database will appear in a textbox or something. I don't know how to do it, so this is why I'm asking :P.

This is an example of something I would like to create: www.factorizer.com

Thank you for your help,
Sam

-SamDave

i have a doubt about randomly generating a string
Visual Basic: Random Strings!

I'm writing a code to display 4 options in radiobuttons , that means I have 4 radiobuttons , I want to generate the answer randomly each time different answers but there much be one answer is correct that means that answer will not be randomly generated ..

My question is how to generate the random strings and keep track of one the right answer .. Even that right answer should not be static (it should be every time in different radiobutton) so the person who's answering the quiz will not be able to remember the place of the radiobutton which has the correct answer .
So will you Please tell me how to do that .
The second question is :
If I want to generate random picture in vb.Net .. How can I do that


-noor

We can only generate Random numbers within a specified range. However, this number can be used as the index for an array so that we can select a random element from the array, be it an array of Strings, Images, or whatever. What I mean to say is that the process to selecting random picture is the same as that of selecting random strings.

Another thing that I must mention is that this whole stuff we have seen above is not generating a random string, rather selecting a random string. Generating random strings would generate something like zxjhtsjbdjgasd or asdxcbjdkhasd. You can however, select a dictionary word from a list or an array. But, it wouldn't be generating either.

Back to the first question:-

I am assuming you have a collection of wrong answers and a correct answer for each question. (You don't want to make the correct one obvious by filling the wrong ones with those randomly generated strings we just saw, do you?) You need to shuffle the correct answer's position (1, 2, 3 or 4) each time and you need to select 3 wrong answers from the wrong answer collection.

I'll be using the function created by ViRuaL.

STEP 1: First we generate the random position of the correct answer and store it in our variable: Dim CorrectCh As Integer = RandomNumber(1, 4)

STEP 2: Set the correct answer as the text for the appropriate Radio Button: Options(CorrectCh - 1).Text = CorrectAnswer

(Assuming Options to be a zero based array of Radio Buttons)

STEP 3: For each of the remaining positions, generate a random number. Using this number we select a random answer from the list/array of wrong answers and set the text of the Radio Buttons accordingly.



Although this code is still not bug free. There's a pretty good chance that the same wrong answer will be repeated. This is because generating a Random Number makes no guarantee that it won't be repeated in the next iteration. To resolve this you can follow either of the ways:-

Method 1

Store the selected answers or their IDs in another array. Whenever a new choice is generated, make sure that this number has not been already generated. If it has been then repeat the process again.



The inner loop can be eliminated by using a HashTable as follows:-



Method 2

This Method is not quite efficient, because the Retry operation may take many iterations if an already generated random number is being generated again. So a better approach is to use a class that generates a non random number. You can find the VB .NET and C# . NET implementation of such a class at http://maxotek.net/blog/?p=9

The following code uses the RandomNumber class declared at http://maxotek.net/blog/?p=9

I have not done VB in a long time, but I assume you can make object arrays (filled with strings and what not), or record arrays maybe.

Use that instead of if/then/else if, and if you have something available like record arrays, add an extra value for primary (or the answer), so say if you load 4 strings from file, 1 will be marked in some manner as the correct answer, mark it as primary.

Then if someone checks a box, check the correspendence between radio button and record array, and check it's primary property to see if it's the correct answer.

Anyway, I do all this stuff in Object Pascal (Delphi), but VB should have something.

Word (Integer)
Visual Basic: Random Strings!

I am currently trying to make a spelling program in which it has 3 levels .
What I'm stuck at is when it comes to coding it how do I get it so words are shown on a label then took off in which you can then right in the text box what word it was. How do I then have random words come up but not have them show again so that the person isnt seeing the same word over and over again.

-question by Paul

You need to generate non-repeating Random numbers. I made a class for the same which can generate non-repeating Random numbers within a specified range or select a non-repeating Random number from a supplied list of numbers. The numbers will be repeated after a complete cycle finishes and all the numbers have been generated once.

You can find the VB.NET code at http://maxotek.net/blog/?p=9

You could modify the code a bit to directly select one of your words stored as string types.



The above code generates Random words based on a supplied list using a String array or as a ParamArray.

random function using in automatically selected question in vb 6.o version
Visual Basic: Random Strings!

Replying to Feedbacker you have a query of question and this query is selected by using random function.

-question by santu

[Replying to turbopowerdmaxsteel,5264,119 669] I tried to use the code you wrote but I get an error on the word New after the Sub New. I have tried several corrections but can't figure it out. What I really want is a way to have a list of 12 or 16 names that can be randomly sorted for a game, so that partners will be different each month. I wrote one in Quick Basic and it worked great but programs written in QB can't be printed through Windows. I would really like to find a way to make one in vb2005Express.

-question by JRichards