Make DbDataReader start reading again from the beginning of the result set

Question

How to make dr.Read(); start reading again from the beginning if a condition is satisfied?

Something like:

SqlDataReader dr = command.ExecuteReader();
for(int i=0; dr.Read() ; i++){
    if(condition ){
        //let dr.Read() start reading from the beginning
    }
}

A data reader is a "fire hose"...as already mentioned..."forward only". That's why it is lean, it doesn't have to "remember" anything 'before'. — granadaCoder, May 03 '13 at 15:00

score 23 · Accepted Answer · answered May 03 '13 at 14:47

23

You can't.

The *DataReader classes are forward-only iterators.

Instead, you can store the results in a List<T> (or a DataTable)

answered May 03 '13 at 14:47

SLaks

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score 6 · Answer 2 · answered May 03 '13 at 14:47

6

The only way to restart it is to grab a new reader with ExecuteReader().

answered May 03 '13 at 14:47

Andomar

232,371
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score 6 · Answer 3 · edited Dec 08 '17 at 18:07

6

You can do that by first closing the datareader using dr.close(); then initializing it again.

If(condition)
{
    dr.close();
    dr=command.ExecuteReader();
}

Where command is the MySqlCommand object.

edited Dec 08 '17 at 18:07

CDspace

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answered Dec 08 '17 at 17:04

danish_wani

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This only works on datareaders with one resultset. Multiple resultsets would reoccur. – Matthias Aug 20 '18 at 13:45

Make DbDataReader start reading again from the beginning of the result set

3 Answers3

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