CustomTaskPaneCollection.Add throws argument exception when project add-in reloaded. RRS feed

  • Question

  • I have developed the project add-in and when I am reloading my add-in from the options-> add-ins, "CustomTaskPaneCollection.Add(UserControl, string)" throws the null argument exception.

    It is only happening for project application, all other office apps add-in the CustomTaskPaneCollection works as expected. Please someone can help me on how to get rid of this below error message.

    System.ArgumentNullException (-2147467261): Value cannot be null.
    Parameter name: o <No inner exception>

    Monday, August 10, 2020 6:24 AM