How do I add a Menuitem to a Menustrip from a DLL

Question

hi well half of the question I've already answered there's no problem modifying an Application's Menustrip you just have to send the DLL the Apps Menustrip-object. The dropdownitems Click-Event does not work. How I did it: DbMenuOwner receives the MenuStrip-Object When the DLL is loaded I check DbMenuOwner and call AddDbMenu(). public override void Load(string databasename) { if (DbMenuOwner != null) AddDbMenu(); } The DLL-Method AddDbMenu looks like this : protected void AddDbMenu() { System.Windows.Forms.ToolStripMenuItem tsmi = new System.Windows.Forms.ToolStripMenuItem(); tsmi.Text = Database; tsiSelect = tsmi.DropDownItems.Add(Select); tsiSelect.Click += new EventHandler(tsiDatabaseSelect_Click); DbMenuOwner.Items.Insert(1 tsmi); } public void tsiDatabaseSelect_Click(object sender EventArgs e) { this.DatabaseUI(); } When I run the Application and click the Select-Item the App crashes. Any ideas what I'm doing wrong here or is there something missing? One important note: I do not want to add any Code to my Application. for your answers many thanks in advance Franz

Franz Heyn · Answer

thanks for your answer the only difference between your suggestion and mine is the MenuStrips public state. In my DLL I do not use a public Method instead I use a public property DbMenuOwner to pass the MenuStrip-Object to the DLL Setting the MenuStrip public however did not solve my problem there's still a nullreference-exception

Tuhin Paul · Answer

In your DLL create a public method that will add the MenuItem to the MenuStrip. This method should take the MenuStrip as a parameter. public class MyDll { public void AddMenuItem(MenuStrip menuStrip) { // Create a new MenuItem ToolStripMenuItem menuItem = new ToolStripMenuItem(My MenuItem); // Add the MenuItem to the MenuStrip menuStrip.Items.Add(menuItem); } } In your main project add a reference to the DLL. In your main project call the AddMenuItem method and pass the MenuStrip as a parameter. public class MainForm : Form { private MenuStrip menuStrip1; public MainForm() { InitializeComponent(); // Create an instance of the DLL MyDll myDll = new MyDll(); // Call the AddMenuItem method myDll.AddMenuItem(menuStrip1); } } Make the MenuStrip accessible public class MainForm : Form { public MenuStrip menuStrip1; }