winform 动态加载菜单，mdiForm不重复加载

C:\Users\Administrator\Desktop\Test\WindowsFormsApplication1\WindowsFormsApplication1\bin\Debug\WindowsFormsApplication1.exe.config C:\Users\Administrator\Desktop\Test\WindowsFormsApplication1\WindowsFormsApplication1\bin\Debug\WindowsFormsApplication1.exe C:\Users\Administrator\Desktop\Test\WindowsFormsApplication1\WindowsFormsApplication1\bin\Debug\WindowsFormsApplication1.pdb C:\Users\Administrator\Desktop\Test\WindowsFormsApplication1\WindowsFormsApplication1\obj\Debug\WindowsFormsApplication1.csprojResolveAssemblyReference.cache C:\Users\Administrator\Desktop\Test\WindowsFormsApplication1\WindowsFormsApplication1\obj\Debug\WindowsFormsApplication1.Properties.Resources.resources C:\Users\Administrator\Desktop\Test\WindowsFormsApplication1\WindowsFormsApplication1\obj\Debug\WindowsFormsApplication1.csproj.GenerateResource.Cache C:\Users\Administrator\Desktop\Test\WindowsFormsApplication1\WindowsFormsApplication1\obj\Debug\WindowsFormsApplication1.exe C:\Users\Administrator\Desktop\Test\WindowsFormsApplication1\WindowsFormsApplication1\obj\Debug\WindowsFormsApplication1.pdb C:\Users\Administrator\Desktop\Test\WindowsFormsApplication1\WindowsFormsApplication1\obj\Debug\WindowsFormsApplication1.FrmMain.resources C:\Users\Administrator\Desktop\Test\WindowsFormsApplication1\WindowsFormsApplication1\obj\Debug\WindowsFormsApplication1.Form1.resources C:\Users\Administrator\Desktop\Test\WindowsFormsApplication1\WindowsFormsApplication1\obj\Debug\WindowsFormsApplication1.Form2.resources