Net ObjectDataSource error: Object does not match target type?

A colleague found the cause of my problem. The AddCommentPresenter class in my web app was defined in the website's App_Code directory. For some reason, that was causing the error.

Move it out of there, into the main directory of the website and the code worked. I can't find any mention in any ObjectDataSource documentation of this being a potential gotcha for the control, but there you go.

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I have an ObjectDataSource on a page that is producing the error "Object does not match target type" when its Insert method is invoked. From Googling this message, I believe this the message is deceptive and I'm actually getting a null reference error on the object that the ObjectDataSource is trying to invoke the method on, but I'm darned if I can figure out why. The Type that is being called upon Insert is an AddCommentPresenter.

The method AddComment is not static. If I change this to static, I don't get the error and the method is found without problem. When it's not static, the error occurs.

That's whyI htink that the underlying problem is that somehow I'm not getting a valid instance of my Presenter class when the AddComment method is invoked. My AddCommentPresenter class doesn't have a parameterless constructor. This will cause an error normally.

To get around it I'm overriding the ObjectCreating event in my page's code-behind and assigning an instance of the Presenter class. Protected void dsAddComment_ObjectCreating(object sender, ObjectDataSourceEventArgs e) { e. ObjectInstance = presenter; } I can step through my ObjectCreating method and it is a valid, non-null Presenter instance that's being passed into the e.

ObjectInstance property. My AddComment method has the correct signature. Public void AddComment(UserComment newComment) { ... } I've also checked the obvious things, like misspelling the type name on the aspx page, but all is correct there.

Anyone have any ideas? I must say that I find the ObjectDataSource class very difficult to work with.... asp.net data-binding objectdatasource 2-way-object-databinding link|improve this question asked Oct 1 '10 at 2:30Treighton264 0% accept rate.

A colleague found the cause of my problem. The AddCommentPresenter class in my web app was defined in the website's App_Code directory. For some reason, that was causing the error.

Move it out of there, into the main directory of the website and the code worked. I can't find any mention in any ObjectDataSource documentation of this being a potential gotcha for the control, but there you go. I've also been told that it should be possible to keep the class in the App_Code folder, but include the syntax ",__code" at the end of the TypeName.

E.g. TypeName="MyNamespace. MyType,__code" but personally, I didn't get that working when I tried it.

Another post to an ASP. Net forum suggested changing the TypeName to TypeName="_MyNamespace. MyType" That didn't work for me, either.

I ended up just pulling the class out of the App_Code folder.

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