格式 function - VB6 到 C# 转换

Question

What is the C# equivalent of:

Public stringValue As String
Public intValue As Integer

intValue = Format(val(stringValue), "00")

?

Answer 1

So the vb6 Format function converts to string and the Val function converts to a number. If you look at the Microsoft documentation for Val :

Val("    1615 198th Street N.E.")
// returns
1615198

in c# this can clumsily be converted to

string stringValue = "    1615 198th Street N.E.";

// assign to int if int wanted
// throws exception if cannot be converted to int, use Int32.TryParse if you want to handle that
int intValue = System.Convert.ToInt32(
    new string(stringValue.Replace(" ", "").TakeWhile(System.Char.IsDigit).ToArray())
);

System.Console.WriteLine(intValue);

it's really going to depend on what your expectations are for what stringValue is going to be and what you want returned. Also I don't think you can assign a string value to an int so willy nilly like you can in vb6. It can definitely be cleaned up but that just depends on what you're doing.

edit: Since you're testing a stringValue = "3" this should work

string stringVal = "3";
if(!System.Int32.TryParse(stringVal, out int intValue))
{
    System.Console.WriteLine($"value={stringVal} not of type int");
}
return intValue;

Answer 2

If truly replicating the VB6 Val function is desired, then Microsoft.VisualBasic.Val can be used. It is pretty faithful to the original, and of course can be called from C#.

See https://docs.microsoft.com/en-us/dotnet/api/microsoft.visualbasic.conversion.val?view=netcore-3.1#Microsoft_VisualBasic_Conversion_Val_System_String_ for the string overload (returns Double).

One aspect where it doesn't return the same result as VB6 is for a string like "3.4.5". VB6 Val will return 34.5, while the.Net Val will return 3.4.

No need for exception handling (just like with VB6), if the input can't be converted to a number, no exception is thrown (well, mostly, there are some edge cases) or error returned, the return value is zero.