Unable to cast object of type 'System.String' to type 'Microsoft.Office.Interop.Outlook.Store

Question

I am developing Outlook add-ins which populates all the available shared mailboxes in to combo box and sends email using the selected mailbox. When I select the mail account from combo box, I get error Unable to cast object of type 'System.String' to type 'Microsoft.Office.Interop.Outlook.Store' Following is the code. Populate combo box. private void MailBoxOptions_Load(object sender, EventArgs e) { Microsoft.Office.Interop.Outlook.Application application = new Microsoft.Office.Interop.Outlook.Application(); Microsoft.Office.Interop.Outlook.NameSpace ns = application.GetNamespace("MAPI"); Stores stores = ns.Stores; foreach (var store in Globals.ThisAddIn.Application.Session.Stores .Cast() .Where(c => c.ExchangeStoreType == Microsoft.Office.Interop.Outlook.OlExchangeStoreType.olExchangeMailbox)) { if (store != null) { mailBoxes.Items.Add(store.DisplayName); } else { MessageBox.Show("You don't have access to any shared mail-inbox."); } } } Code for Combo box public void comboBox1_SelectedIndexChanged(object sender, EventArgs e) { var selectedStore = (Store)mailBoxes.SelectedItem; } Any help would be appreciated. Thanks. JavaScript questions and answers, JavaScript questions pdf, JavaScript question bank, JavaScript questions and answers pdf, mcq on JavaScript pdf, JavaScript questions and solutions, JavaScript mcq Test , Interview JavaScript questions, JavaScript Questions for Interview, JavaScript MCQ (Multiple Choice Questions)

Answer 1

With mailBoxes.Items.Add(store.DisplayName); you are adding the display name of the store as string to the ComboBox. And that's exacly what you get in return with mailBoxes.SelectedItem. Of course you cannot cast this string to Store. You could wrap the store in a display class public class StoreDisplay { public StoreDisplay(Store store) { this.Store = store; } public Store Store { get; } public override string ToString() ==> Store.DisplayName; } Then you can add items to the ComboBox with mailBoxes.Items.Add(new StoreDisplay(store)); Because ToString has been overridden, the ComboBox will show the DisplayName or every store item. Finally, you can retrive the store with var selectedStore = ((StoreDisplay)mailBoxes.SelectedItem)?.Store; if (selectedStore != null) { ... } You can also try to add the Store objects directly to the ComboBox; however, I don't know if they will display correctly. A side note: If you have conflicting type names or if you simply want shorter namespace references, you can use namespace aliases using MsOl = Microsoft.Office.Interop.Outlook; using AppSession = Globals.ThisAddIn.Application.Session; and use it like this var application = new MsOl.Application(); MsOl.NameSpace ns = application.GetNamespace("MAPI"); Stores stores = ns.Stores; foreach (var store in AppSession.Stores .Cast() .Where(c => c.ExchangeStoreType == MsOl.OlExchangeStoreType.olExchangeMailbox)) { ... }