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1. The #define and #undef preprocessor directives must be used at the beginning of a program, before any other keywords, such as those used in the namespace declaration.<br />
2. The #define directive cannot be used to declare constant values as is typically done in C and C++. Constants in C# are best defined as static members of a class or struct. If you have several such constants, consider creating a separate &quot;Constants&quot; class to hold them. <br />
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See:<br />
<a href="http://msdn.microsoft.com/en-us/library/47hya4cw%28v=vs.71%29.aspx" rel="ugc">http://msdn.microsoft.com/en-us/library/47hya4cw%28v=vs.71%29.aspx</a><br />
<a href="http://msdn.microsoft.com/ru-ru/library/yt3yck0x.aspx" rel="ugc nofollow">http://msdn.microsoft.com/ru-ru/library/yt3yck0x.aspx</a>
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Thats mean i can't declare #define. Instead of using #define, i must use public const ?
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What are you using the #define for? &nbsp;If you are trying to use it for conditional compilation, then there are other ways to define...
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Hi,<br />
<br />
Every time when i declare #define TITO 2;<br />
error message -&gt; cannot define/ undefine preprocessor sysmbols after first token file. Is there any error on define method?
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Hi,

Every time when i declare #define TITO 2;
error message -> cannot define/ undefine preprocessor sysmbols after first token file. Is there any error on define method?

1. The #define and #undef preprocessor directives must be used at the beginning of a program, before any other keywords, such as those used in the namespace declaration.
2. The #define directive cannot be used to declare constant values as is typically done in C and C++. Constants in C# are best defined as static members of a class or struct. If you have several such constants, consider creating a separate &quot;Constants&quot; class to hold them. 

See:
http://msdn.microsoft.com/en-us/library/47hya4cw%28v=vs.71%29.aspx
http://msdn.microsoft.com/ru-ru/library/yt3yck0x.aspx

Thats mean i can&#39;t declare #define. Instead of using #define, i must use public const ?

What are you using the #define for?  If you are trying to use it for conditional compilation, then there are other ways to define...

how to use #define in window form in C#

Hi,

Every time when i declare #define TITO 2;
error message -&gt; cannot define/ undefine preprocessor sysmbols after first token file. Is there any error on define method?

The .NET Framework is not specific to any one programming language; rather, it includes a library of functions that allows developers to rapidly build applications. Several supported languages include C#, VB.NET, C++ or ASP.NET.

.NET Programming

C# is an object-oriented programming language created in conjunction with Microsoft’s .NET framework. Compilation is usually done into the Microsoft Intermediate Language (MSIL), which is then JIT-compiled to native code (and cached) during execution in the Common Language Runtime (CLR).