VB6 question

[Airhog]

I have 2 Simple Questions

If (TxtDiceSides.Text < 2) Or (TxtDiceSides.Text > 100) Or (TxtDiceNumber.Text < 1) Or _
(TxtDiceNumber.Text > 6) Or (TxtDiceSides.Text = "") Or (TxtDiceNumber.Text = "") Then
    Error2 = MsgBox("Please input a number from 2-100", vbOKOnly, "error")
End If

Question 1. If I have a blank value in txtdicenumber.text or a letter then I get a type mismatch error. How can I alter this statment so it doesnt give me that error?

Question 2. The program is supposed to generate a random number for a certain number of dices with a certain number of sides on each dice. Right now I have a subroutine for each Dice from 1-6. And I just call each one as they are needed. I know there is probably a better way to roll the dice for each text box, then move to the next text box. Can you give me a nudge in the right direction here? Im not sure how or If I can use a loop here to increment the text box to place the number in.

[Wolfpack]

I've done a diceroller myself in VB, though I didn't make it robust enough to handle letters being inputted. At any rate, to address that, here's a link I found in a Google search with some suggestions:

http://www.vbcity.com/forums/topic.asp?tid=3785

As to the second point about controlling all the separate textboxes, I'd actually advise not doing so. It's easier to have one textbox output and just daisy-chain all the rolls into it, unless you have something specific in mind for each die. A for loop like the following would work:

    For I = 1 To varNumberOfDice
        varDiceRolled = Int((Rnd * varNumberOfSides) + varLowestValue)
        If I = 1 Then
            strDiceRolled = varDiceRolled
          Else
            strDiceRolled = strDiceRolled & ", " & varDiceRolled
        End If
    Next
    lblDiceRolled.Caption = strDiceRolled

I used variants (for something simple like this, no harm in it) to handle the aspects of the rolling and then a label made to look like a textbox to display the output. I also have an additional feature to total up the dice rolled, but you didn't mention anything for that, so I left it out for brevity. The other advantage to "stringing" the numbers out in a label is that you can roll a very large number of dice, though it does make it difficult to pick out the one you are looking for. You could change the logic of the output so that it puts one die on each line, so there's that.

One thing I'd like to do is add features to roll different combinations of dice, but it would probably mean a redesign to handle something like that.

[Buccaneer]

In regards to #1, probably something along the lines of checking for Null value like varchar() = vbNull - but that's more of a database check.

[Airhog]

Wolfpack: I want it to show each dice, since I modeled after dice used for D&D. But I plan to play around with it some more.

Buccaneer: I checked around and read that null value is equal to zero in VB. That is different from an Empty string. I will look at some more null value examples and try to piece together what I am doing wrong.

[GoldenEagle]

If Text = "" Then msgBox Error

This code screams for a case statement.

[21C]

You can also adjust it to read:

If Val(TxtDiceSides.Text) < 2 etc.

You are comparing the contents of a string/text (TxtDiceSides.Text) to an integer (2). The Val will convert the string to a number.

Val(2) = 2
Val(147) = 147
but
Val(" ") = 0
Val("F") = 0

[Shaun Sullivan]

dim lSides as long
lSides = val(TxtDiceSides.Text)

dim lDice as long
lDice = val(TxtDiceNumber.Text)

if (lSides < 2) or (lSides > 100) or (lDice < 1) or (lDice > 6) then
' Do your "invalid" processing here...
end if

[Airhog]

Shaun Sullivan: that makes sense I think. Ill try that out. Thanks

[Greyroofoo]

numerical variables are automatically initialized to 0 in vb and strings are created blank. My only question is why there are so many "Or"s

how much could I get VB6 for anyways?

[Airhog]

Shaun: Worked like a charm. I see now how that relationship works, and I think I was just trying to get too much use from the TXTnumber.text string.

GE: You think? I think its easier to just define all of the variable in the beginning. Especially since each result gives the same error message.

[sterlingice]

Originally Posted by Greyroofoo

numerical variables are automatically initialized to 0 in vb and strings are created blank. My only question is why there are so many "Or"s

how much could I get VB6 for anyways?

A while back, Microsoft was giving away free copies of VB.Net but I went to the page and saw this: "Due to overwhelming demand, supplies of the complimentary Not For Resale copies of Visual Basic .NET 2003 Standard Edition* are now exhausted. Tens of thousands were claimed by developers. If you wish to explore Visual Basic .NET on a trial basis, visit the Visual Studio .NET 2003 Hosted Experience."

Many of which I saw on ebay despite their not-for-resale tag (so beware if you buy a copy there).

If you have to have vb.6, then I don't know what to say. But I bought my copy of vb.net Student Edition for $100 which seemed pretty reasonable to me.

SI

[Mr. Wednesday]

Originally Posted by Airhog

Buccaneer: I checked around and read that null value is equal to zero in VB. That is different from an Empty string. I will look at some more null value examples and try to piece together what I am doing wrong.

That is not correct. A null value is a null value -- it is distinct from anything else, actually a separate variable type enumeration for a variant. It's definitely not equal to zero. It's something that may actually be set explicitly using the Null keyword (unlike a couple of other variant types, missing and empty, that may only be set using hackery).

[Mr. Wednesday]

Originally Posted by Airhog

Question 1. If I have a blank value in txtdicenumber.text or a letter then I get a type mismatch error. How can I alter this statment so it doesnt give me that error?

Check for an empty string or other non-numeric input prior to checking against a numeric value. Your problem was that you would trip an error on one of the range checks prior to the check that would actually pick up an empty string (never mind never checking for non-numeric input).

Note that it's not enough to move the check for an empty string to the head of the comparison list, unlike with C or C++, because VB doesn't do short-circuit logical operators.

[Airhog]

Originally Posted by Mr. Wednesday

That is not correct. A null value is a null value -- it is distinct from anything else, actually a separate variable type enumeration for a variant. It's definitely not equal to zero. It's something that may actually be set explicitly using the Null keyword (unlike a couple of other variant types, missing and empty, that may only be set using hackery).

I could have swore that I read that somewhere. Thanks for the Clarification

[Mr. Wednesday]

Originally Posted by 21c

You can also adjust it to read:

If Val(TxtDiceSides.Text) < 2 etc.

You are comparing the contents of a string/text (TxtDiceSides.Text) to an integer (2). The Val will convert the string to a number.

Val(2) = 2
Val(147) = 147
but
Val(" ") = 0
Val("F") = 0

Be careful with Val, it is not locale-aware (less of a problem with integer values than floating point values). Alternatively, consider using Clng with some error handling to do something sensible for the cases that give a type mismatch.