应用程序不包含定义

Question

I have a C# forms application. I import an additional CS file into the program and now it doesn't compile any more. Every time I try compile i get the following messages:

Application does not contain a definition for 'EnableVisualStyles'
Application does not contain a definition for 'SetCompatibleTextrenderingDefault'
Application does not contain a definition for 'Run'

When I click on the errors it bring me to Programs.cs. It just contains the following information:

/// <summary>
/// The main entry point for the application.
/// </summary>
[STAThread]
static void Main()
{
    Application.EnableVisualStyles();
    Application.SetCompatibleTextRenderingDefault(false);
    Application.Run(new Form1());
}

Any help would be appreciated.

One more point, a test console app works fine, however I want this app to be forms application.

Answer 1

You added a new using statement for a namespace that has another definition of Application , (it might be your own) and that is taking precedence. You can use the fully qualified name to be sure that you're targeting the right Application class:

global::System.Windows.Forms.Application.EnableVisualStyles();
global::System.Windows.Forms.Application.SetCompatibleTextRenderingDefault(false);
global::System.Windows.Forms.Application.Run(new Form1());

(You can omit the global:: as long as you don't also have a class named System but the above is just a tad more robust in the fact of ambiguous namespace/class names.

Other alternatives include renaming the custom Application class, if it is indeed your own, not adding a using for whatever namespace it's in for this file (or any file that uses the System.Windows.Forms Application class), adding an alias for System.Windows.Forms.Application (this is done by something like using FormApplication = System.Windows.Forms.Application; ), etc.

Answer 2

I ran into this problem when using the Entity Model Framework to connect to a database that happened to have a table named "Application". Once the classes were generated for the database, I immediately had two "Application" classes which caused the error in question. In my Program.cs file's Main() method, the following code change fixed the issue:

System.Windows.Forms.Application.EnableVisualStyles();         
System.Windows.Forms.Application.SetCompatibleTextRenderingDefault(false);
System.Windows.Forms.Application.Run(new MyForm());

Answer 3

I know this is a necro-bump but it applies to my situation today. @James G's answer above made me realize that I had imported a web service that contained a definition for "Application" which also caused this error. As part of your checking things, make sure that any imported services don't incidentally contain "Application."

If anyone is importing it, DynamicsSecurityAdminService is the one that did it to me.