C# to VB translation problem

  • Thread starter Thread starter B. Chernick
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B. Chernick

I have a little problem I'm not clear on. I program mostly in VB, I am
somewhat familiar with C#, and I've been told to translate a program. I was
under the general impression that since C# and VB are both Dot Net languages,
it was more or less possible to directly translate everything, aside from a
few individual language quirks.

In the original C# I have the following:
foreach (AccountInfo item in Accounts)
{
if (item.LastChangedBy != null)
{
... do some stuff here.
}
}

where LastChangedBy is an integer property of the object AccountInfo

My freeware translator has rendered this in VB as:
For Each item As AccountInfo In Accounts
If item.LastChangedBy IsNot Nothing Then

VS does not like this and gives an error: 'IsNot' requires operands that
have reference types, but this operand has the value type 'Integer'.

How would you translate this?
 
I have a little problem I'm not clear on. I program mostly in VB, I am
somewhat familiar with C#, and I've been told to translate a program. I was
under the general impression that since C# and VB are both Dot Net languages,
it was more or less possible to directly translate everything, aside from a
few individual language quirks.

In the original C# I have the following:
foreach (AccountInfo item in Accounts)
{
if (item.LastChangedBy != null)
{
... do some stuff here.
}

}

where LastChangedBy is an integer property of the object AccountInfo

My freeware translator has rendered this in VB as:
For Each item As AccountInfo In Accounts
If item.LastChangedBy IsNot Nothing Then

VS does not like this and gives an error: 'IsNot' requires operands that
have reference types, but this operand has the value type 'Integer'.

How would you translate this?
Click to expand...

Can you verify the type of LastChangedBy? Even in C# you can't
compare an integer to null. You would get a similar compile error in
C# as well. LastChangedBy must be something other than integer.

Chris
 
B. Chernick said:
I have a little problem I'm not clear on. I program mostly in VB, I am
somewhat familiar with C#, and I've been told to translate a program. I was
under the general impression that since C# and VB are both Dot Net languages,
it was more or less possible to directly translate everything, aside from a
few individual language quirks.

In the original C# I have the following:
foreach (AccountInfo item in Accounts)
{
if (item.LastChangedBy != null)
{
... do some stuff here.
}
}

where LastChangedBy is an integer property of the object AccountInfo

My freeware translator has rendered this in VB as:
For Each item As AccountInfo In Accounts
If item.LastChangedBy IsNot Nothing Then

VS does not like this and gives an error: 'IsNot' requires operands that
have reference types, but this operand has the value type 'Integer'.

How would you translate this?
Click to expand...

If LastChangedBy is indeed an int then item.LastChangedBy != null is
always true so you could simply remove the if check and only include the
block e.g.


foreach (AccountInfo item in Accounts)
{
{
... do some stuff here.
}
}

which then becomes

For Each item As AccountInfo In Accounts
... do some stuff here
Next
 
I guess that you have in c# a nullable int delclared: int? LastChangedBy

If so, then the property in vb should be declared as: Nullable(Of Integer)
 
Actually no. The original local variable is declared:
private int _lastChangedBy = 0;
The property itself looks conventional.

However I should explain that the overall application is written using CSLA
2.1.4 and the programmer who wrote it just left on a long vacation without
leaving a scrap of documentation. Then management told me to translate it
using whatever freeware I could find. I barely knew CSLA existed before this
week. I love this job.

(Let me make a guess here. In the original C#, the class itself is declared
public class AccountInfo : Csla.BusinessBase<AccountInfo>
Could this have something to do with the ability of C# to test for nulls
with an integer property in this situation? But this won't translate to VB?)
 
Try

For Each item As AccountInfo In Accounts
If item.LastChangedBy <> DBNull.Value Then
...

Rich
 
Looks like you're right. I compiled the original C# code and got a warning
for the same line stating that 'The result of the expression is always 'true'
since a value of type 'int' is never equal to 'null' of type 'int?'.

I'm going to treat this as a 'political' problem, if you know what I mean....
 
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