How to convert a datareader to datatable

Question

I have a question about converting a datareader to a datatable. In my code, I have a datareader created in one class and passed to another class that I want to convert it to a datatable.

When I do this, it does not seem to work, as the table remains empty. If I do the conversion in the same function, it works fine.

Its only when I pass the datareader to another function that it stops working. Is this because the dr is closed or something? How do I overcome this problem? Any help would be great.

You should never pass DataReader's as you will completely miss to dispose the objects or several times the data will not be there anymore. Can you edit the method that is in use, the one before returning the DataReader? So for example you can add a DataTable property to that method and populate it prior to the return so you can grab outside that class... — balexandre
– balexandre, Commented Feb 23, 2012 at 12:40
no, i was instructed to only return a datareader. the logic being that the function that passes the datareader can be used elsewhere — jason
– jason, Commented Feb 23, 2012 at 12:47

Ben · Accepted Answer · 2013-04-22 14:20:10Z

55

Use DataTable Load() method.

 // Given a DataReader called "reader"
 DataTable dt = new DataTable();
 dt.Load(reader)

answered Apr 22, 2013 at 14:20

Ben

35.8k6 gold badges81 silver badges117 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Arkane Over a year ago

Does reader.Read() need to be called before? If there are multiple rows in the reader, are they all copied to the DataTable?

Ben Over a year ago

You do not need to call Read before. It is probably best if you don't. My guess is you will miss the first record if you do.

HndlCode · Accepted Answer · 2012-02-23 12:50:30Z

2

Check this out:

Public Function ExecuteQuery(ByVal s As String, ByVal condb As SqlConnection, ByVal ParamArray params() As SqlParameter) As DataTable
        Dim dt As DataTable = Nothing
        Using da As New System.Data.SqlClient.SqlDataAdapter(s, condb)               
            dt = New DataTable
            If params.Length > 0 Then
                da.SelectCommand.Parameters.AddRange(params)
            End If
            If da.SelectCommand.Connection.State <> ConnectionState.Open Then da.SelectCommand.Connection.Open()
            da.Fill(dt)                    
        End Using
        Return dt
End Function

answered Feb 23, 2012 at 12:50

HndlCode

1155 bronze badges

2 Comments

jason Over a year ago

thanks for the response. is there anyway to do this without knowing the connection or parameters? The only thing that I'm passed is the datareader. thanks

HndlCode Over a year ago

ParamArray is optional so you dont need to pass any parameter :), please mark my anser as Right

Ahmet OYMACI · Accepted Answer · 2024-11-03 10:33:00Z

0

You do not need to call Read before. It is probably best if you don't. My guess is you will miss the first record if you do.

İnce bir hata için uyarınız çok iyi, teşekkür ederim

answered Nov 3, 2024 at 10:33

Ahmet OYMACI

111 bronze badge

Collectives™ on Stack Overflow

How to convert a datareader to datatable

3 Answers 3

2 Comments

2 Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

2 Comments

2 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related