How to check if an item has already been added?

How to check if an item has already been added?

‘ An item with the same key has already been added.’. The query in question pulls the same table from 4 separate databases and does not modify the data in any way.

What does it mean when an item with the same key has already been added?

When I clicked the details button I got this further information: “An item with the same key has already been added.” Here’s a screen shot of my error. Well this had me scratching my head, as I had made sure to run the stored procedure, and it executed with no errors.

When to use argumentexception an item has already been added?

[ArgumentException: An item with the same key has already been added.] You need to add more context to this. Show us the controller code and describe the exact actions you are taking. Do a little debugging on your own so that your questions are more verbose and not just giant lumps of code/stack. – Chev Apr 14 ’11 at 2:50

What is an item with the same key has already been added?

Error: An item with the same key has already been added. Key: (System.Collections.Immutable, neutral, b03f5f7f11d50a3a) Error: An item with the same key has already been added. Key: (System.Net.Http.Extensions, neutral, b03f5f7f11d50a3a) I’m not sure if these are exactly the same libraries and a binding redirect would solve the problem.

Is there a user with this name already exists?

In Microsoft Office 365, you receive an error message that’s like the following in the Microsoft Office 365 portal: A user with this name already exists. Use a different name. This issue may occur if the user name is already used or if an existing email address that’s based on the user name already exists.

[ArgumentException: An item with the same key has already been added.] You need to add more context to this. Show us the controller code and describe the exact actions you are taking. Do a little debugging on your own so that your questions are more verbose and not just giant lumps of code/stack. – Chev Apr 14 ’11 at 2:50