InvalidOperationException: There is already an open DataReader associated with this Command which...

spottedmahn
spottedmahn
in General

When I try to run 2 ExecuteQueryDynamic()'s, I get:

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

sample code:

//works
ExecuteQueryDynamic("SELECT TOP 1 * FROM Customers").Dump();

//doesn't work
ExecuteQueryDynamic("SELECT TOP 1 * FROM Customers").Dump();

reference: https://stackoverflow.com/a/27750602/185123

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Comments

  • JoeAlbahari
    JoeAlbahari

    I can't reproduce this in LINQPad 6 or LINQPad 5. Is it a standard LINQ-to-SQL connection? Is there any other info you can provide?

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  • ssswwn
    ssswwn

    It seems to make doing the dump in between
    //works
    var ret = ExecuteQueryDynamic("SELECT TOP 1 * FROM Customers");
    ret.Dump();
    //doesn't work
    var ret2 = ExecuteQueryDynamic("SELECT TOP 1 * FROM Customers");
    ret2.Dump();

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  • nescafe
    nescafe

    This issue is reproducible in Results to Data Grids mode.

    You can solve this by iterating the IEnumerable manually, to make sure each reader is executed once during execution.

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