C# how to get list of columns using getschema method

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VS2012

Hi everyone!

I am trying to retrieve a list of columns in a particular table in the database. Here is what I have so far:

var dtCols = conn.GetSchema("Columns", new[] { "waveform_db", null, "Electrical" });

Is this a proper way? If so, how can I access this list to add to a combobox? Here is what I have so far.

C#

if (dtCols != null)
                    {
                        foreach (var dr in dtCols)
                        {
                            // code to add to combobox
                        }
                    }

The compiler is balking at the beginning of the foreach statement.
"foreach statement cannot operate on variables of type "system.data.datatable" because "system.data.datatable" does not contain a public definition for "getenumerator".

I'm not real sure what this means. Does anyone have any hints as to how to resolve this issue?

Thanks everyone!

Posted 21-Jan-13 7:44am

joshrduncan2012

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Wietze Bron · Answer 1 · 2013-01-21T07:52:00

You could do it like this:

VB

Try
    Dim SQLConnection As SqlConnection = New SqlConnection()
    SQLConnection.ConnectionString = DBconnectionWork
    Dim SQLCommand As SqlCommand = SQLConnection.CreateCommand()
    SQLCommand.CommandText = "select c.name from syscolumns c (nolock), sysobjects o (nolock) " + _
                             "where c.id = o.id and o.name = 'tablename' " + _
                             "  and c.name <> 'timestamp' " + _
                             "order by colid"
    SQLConnection.Open()
    Dim myReader As SqlDataReader = SQLCommand.ExecuteReader()
    Do While myReader.Read()
        ComboBox1.Items.Add(myReader.GetString(0))
    Loop
    myReader.Close()
    SQLConnection.Close()
Catch ex As Exception
    MsgBox(ex.ToString, MsgBoxStyle.Critical)
End Try

Adam R Harris · Answer 2 · 2013-01-21T09:04:00

Solution 2

C#

foreach (DataRow dr in dtCols.Rows)

Your specific error is because you need to iterate the Rows of the DataTable not the DataTable itself.

However:
Wietze Bron is correct, his method is exactly what you need.

Posted 21-Jan-13 9:04am

Adam R Harris