Calling optional parameterized method in c#

[Krishnaraj Barvathaya B]

Hi All, I have COM component which is referred in my C# application. Visual studio has generated interop for the COM and able to call the methods from C# code. This component has a method with parameters being optional. Now I am not able to force the compiler to use default values of these optional parameter instead of explicitly passing them. In other words I don’t want to pass any values to call this method. I tried using System.Reflection.Missing.Value. but it throw error saying type missmatch. Method is looking for integer type value. Is there any I can call this method without passing any parameters and creating a wraper to this assembly. Thank you,

Krishnaraj Barvathaya B

[DaveyM69]

Optional parameters don't exist in C# unfortunately. The best you can do is create an overload and have the overload call the full method. I hate to say it, but you can do this in VB! There was talk of it being introduced into C#4 but I don't know if it's made it or not.

void Method(int a)
{
Method(a, 0);
}
void Method(int a, int b)
{
}

Dave
BTW, in software, hope and pray is not a viable strategy. (Luc Pattyn)
Visual Basic is not used by normal people so we're not covering it here. (Uncyclopedia)

[Dave Kreskowiak]

I'm pretty sure optional parameters made it in. There's an inititive to introduce new features to both C# and VB.NET at the same time. This also means syncronizing the existing feature sets between the two languages where appropriate. For example, C# gets the optional parameters VB.NET supports, but VB.NET does NOT get the unsafe code and pointer support that C# has. :( At least, not yet...

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[Scott Dorman]

Optional parameters did make it in to the underlying IL but they aren't exposed in C# yet (C# 4.0 will support them). There is an effort to keep the two languages more in-sync with one another but it isn't across the board with all language features, as you mentioned. Another exmaple is that C# will not get the "XML literal" syntax VB supports.

Scott Dorman

Microsoft® MVP - Visual C# | MCPD President - Tampa Bay IASA [Blog][Articles][Forum Guidelines]

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[Krishnaraj Barvathaya B]

Thank you every one for your answers. From your answers I am able to conclude that there is no straight forward way to call a method with optional parameter by forcing to use its default value. So I created a wrapper class in VB.net with number of overloaded methods to match its optional implementation. Looks to be working fine.

Krishnaraj Barvathaya B

[Dave Doknjas]

For the parameters you're not interested in, just pass either: System.Type.Missing System.Reflection.Missing.Value (either will work)

David Anton http://www.tangiblesoftwaresolutions.com C++ to C# Converter C++ to VB Converter C++ to Java Converter VB & C# to Java Converter Java to VB & C# Converter Instant C#: VB to C# converter Instant VB: C# to VB converter Instant C++: convert VB, C#, or Java to C++

[Krishnaraj Barvathaya B]

This will work only in case the expected parameter is of reference type such as string. It doesn’t work if the method is looking for Integer type or any other primitive types. If you pass either System.Reflection.Missing. System.Type.Missing or System.Reflection.Missing.Value compiler shows up error saying type mismatch. So after lot of search, I think there is only way to break this barrier is by creating a wrapper class in VB.net and referencing the same.

Krishnaraj Barvathaya B