Why .NET does not allow cross-thread operations? [duplicate]

This question already has answers here: Closed 12 years ago.

Possible Duplicate:

.NET Controls: Why aren’t all calls thread-safe?

This question i开发者_JAVA技巧s not about what is a cross-thread operation, and how to avoid it, but why internal mechanics of .NET framework does not allow a cross-thread operation.

I can`t understand why a SerialPort DataReceived event cannot update a simple text box on my form and why using delegates this is possible?

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.NET allows cross-thread operations. But you should handle it safely. Use Invoke / BeginInvoke methods for cross-thread operations. Invoke means "Hey, text box! Please update yourself when you will have time." Here is an example of usage on MSDN