如何在Asp.net C#中解决此编译器错误

The type or namespace name 'TypeName' could not be found (are you missing a using directive or an assembly reference?)

using System; // 示例

No overload for method 'MethodName' takes 'number' arguments

public void MyMethod(int a, string b) { }
// 调用时
MyMethod(1, "test"); // 正确
MyMethod("test"); // 错误

CS0006: Metadata file 'filename.dll' could not be found

CS1001: Identifier expected

int x = 10; // 正确
int y // 错误，缺少分号

CS0246: The type or namespace name 'MyNamespace' could not be found (are you missing a using directive or an assembly reference?)

using MyNamespace; // 添加using指令