There is already an open DataReader associated with this Command which must be closed first. code example

Example 1: There is already an open DataReader associated with this Command which must be closed first c#

<connectionStrings>
    <add name="IdentityConnection" connectionString="Data Source=(LocalDb)\v11.0;AttachDbFilename=|DataDirectory|\IdentityDb.mdf;Integrated Security=True;MultipleActiveResultSets=true;" providerName="System.Data.SqlClient" />
  </connectionStrings>

Example 2: There is already an open DataReader associated with this Command which must be closed first.

Add this to your connection string:
MultipleActiveResultSets=true;

Example 3: There is already an open DataReader associated with this Connection which must be closed first.

there is already an open datareader associated with this command which must be closed.