VB to C# Functions

Question

Which are the equivalent of the following operators from VB.Net to C#?

• UBound()
• LBound()
• IsNothing()
• Chr()
• Len()
• UCase()
• LCase()
• Left()
• Right()
• RTrim()
• LTrim()
• Trim()
• Mid()
• Replace()
• Split()
• Join()
• MsgBox()
• IIF()

Answer 1

Most of these would be instance methods on the string object that return the modified string.

MsgBox vs. MessageBox.Show(..)

IIF vs. (expression?returnValueIfTrue:returnValueElse)

Answer 2

IIf(test, trueval, falseval) >> (test ? trueval : falseval);

IsNothing(obj) >> (obj == null);

UCase(str) >> str.ToUpper();

LCase(str) >> str.ToLower();

Answer 3

VB             C#

UBound()     = yourArray.GetUpperBound(0) or yourArray.Length for one-dimesional arrays
LBound()     = yourArray.GetLowerBound(0)
IsNothing()  = Object.ReferenceEquals(obj,null)
Chr()        = Convert.ToChar()
Len()        = "string".Length
UCase()      = "string".ToUpper()
LCase()      = "string".ToLower()
Left()       = "string".Substring(0, length)
Right()      = "string".Substring("string".Length - desiredLength)
RTrim()      = "string".TrimEnd()
LTrim()      = "string".TrimStart()
Trim()       = "string".Trim()
Mid()        = "string".Substring(start, length)
Replace()    = "string".Replace()
Split()      = "string".Split()
Join()       = String.Join()
MsgBox()     = MessageBox.Show()
IIF()        = (boolean_condition ? "true" : "false")

Notes

• yourArray.GetUpperBound(0) vs yourArray.Length: if the array is zero-length, GetUpperBound will return -1, while Length will return 0. UBound() in VB.NET will return -1 for zero-length arrays.
• The VB string functions uses a one based index, while the .NET method uses a zero based index. I.e. Mid("asdf",2,2) corresponds to "asdf".SubString(1,2).
• ? is not the exact equivalent of IIf because IIf always evaluates both arguments, and ? only evaluates the one it needs. This could matter if there are side effects of the evaluation ~ shudder!
• The Many classic VB String functions, including Len(), UCase(), LCase(), Right(), RTrim(), and Trim(), will treat an argument of Nothing (Null in c#) as being equivalent to a zero-length string. Running string methods on Nothing will, of course, throw an exception.
• You can also pass Nothing to the classic VB Mid() and Replace() functions. Instead of throwing an exception, these will return Nothing.

Answer 4

In addition to the answers above. Be carefull with replacing Len() -> x.Length. VB Len() allows you to pass null, but in c# you will get an exception. Sometimes it would be better to use String.IsNullrEmpty() (If the situation allows)

Answer 5

All these functions are member methods of the Microsoft.VisualBasic.Information class, in the Microsoft.VisualBasic assembly, so you can use them directly. However, most of them have C# equivalents, or non language specific equivalents in core .NET framework classes :

• UBound() : Array.GetUpperBound
• LBound() : Array.GetLowerBound
• IsNothing() : == null
• Chr() : (char)intValue (cast)
• Len() : String.Length
• UCase() : String.ToUpper
• LCase() : String.ToLower
• Left(), Right() and Mid() : String.Substring (with different arguments)
• RTrim() : String.TrimEnd
• LTrim() : String.TrimStart
• Trim() : String.Trim
• Replace() : String.Replace
• Split() : String.Split
• Join() : String.Join
• MsgBox() : MessageBox.Show
• IIF() : condition ? valueIfTrue : valueIfFalse (conditional operator)

Links

• Array members
• String members
• MessageBox.Show
• conditional operator

Answer 6

I believe some of these like Mid() are still available in the .NET Framework in the Microsoft.VisualBasic namespace which you can still reference from C# code.