The exception that is thrown when an attempt to load a class fails due to the absence of an entry method.
See Also: EntryPointNotFoundException Members
An EntryPointNotFoundException exception is thrown when the common language runtime is unable to load an assembly because it cannot identify the assembly's entry point. This exception can be thrown under the following conditions:
The common language runtime is unable to locate an application entry point (typically a Main method) in an executable assembly. The application entry point must be a global or static method that has either no parameters or a string array as its only parameter. The entry point can return void, or it can return an int or uint exit code. An application assembly cannot define more than one entry point.
The call to a function in a Windows DLL cannot be resolved because the function cannot be found. In the following example, an EntryPointNotFoundException exception is thrown because User32.dll does not include a function named GetMyNumber.
code reference: System.EntryPointNotFoundException.Class#1
The call to a function in a Windows DLL cannot be resolved because the name used in the method call does not match a name found in the assembly. Frequently, this occurs because the System.Runtime.InteropServices.DllImportAttribute.ExactSpelling field is either implicitly or explicitly set to true, the called method includes one or more string parameters and has both an ANSI and a Unicode version, and the name used in the method call does not correspond to the name of this ANSI or Unicode version. The following example provides an illustration by attempting to call the Windows MessageBox function in User32.dll. Because the first method definition specifies System.Runtime.InteropServices.CharSet.Unicode for string marshaling, the common language looks for the wide-character version of the function, MessageBoxW, instead of the name used in the method call, MessageBox. The second method definition corrects this problem by calling the MessageBoxW instead of the MessageBox function.
code reference: System.EntryPointNotFoundException.Class#2
You are trying to call a function in a dynamic link library by its simple name rather than its decorated name. Typically, the C++ compiler generates a decorated name for DLL functions. For example, the following C++ code defines a function named Double in a library named TestDll.dll.
code reference: System.EntryPointNotFoundException.Class#6
When the code in the following example tries to call the function, an EntryPointNotFoundException exception is thrown because the Double function cannot be found.
code reference: System.EntryPointNotFoundException.Class#7
However, if the function is called by using its decorated name (in this case, ?Double@@YAHH@Z), the function call succeeds, as the following example shows.
code reference: System.EntryPointNotFoundException.Class#8
You can find the decorated names of functions exported by a DLL by using a utility such as Dumpbin.exe.
You are attempting to call a method in a managed assembly as if it were an unmanaged dynamic link library. To see this in action, compile the following example to an assembly named StringUtilities.dll.
code reference: System.EntryPointNotFoundException.Class#3
Then compile and execute the following example, which attempts to call the StringUtilities.SayGoodMorning method in the StringUtilities.dll dynamic link library as if it were unmanaged code. The result is an EntryPointNotFoundException exception.
code reference: System.EntryPointNotFoundException.Class#4
To eliminate the exception, add a reference to the managed assembly and access the StringUtilities.SayGoodMorning method just as you would access any other method in managed code, as the following example does.
code reference: System.EntryPointNotFoundException.Class#5
You are trying to call a method in a COM DLL as if it were a Windows DLL. To access a COM DLL, select the Add Reference option in Visual Studio to add a reference to the project, and then select the type library from the COM tab.
For a list of initial property values for an instance of EntryPointNotFoundException, see the EntryPointNotFoundException.#ctor constructors.