Server Error in '/.Net' Application.
The ConnectionString property has not been initialized.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
Exception Details: System.InvalidOperationException: The ConnectionString property has not been initialized.
Cause
The ConnectionString property of SqlConnection object is not set or it is invalid.
Solution
1. Check you are assigning value to SqlConnection Object or not. For more information you can visit my article Parameterized Queries ADO.Net. I have explained how to get connection string from web.config
2. If connection string is coming from web.config check the key name is correct.
3. If the variable is used it is not reset somewhere