In vb.net, how to get the column names from a datatable

So i create a datatable from a table i can't directly view(i.e. us开发者_JS百科ing sql server management). I want to find the column names that are in the datatable, what would be the correct way do this?

This is how to retrieve a Column Name from a DataColumn:

MyDataTable.Columns(1).ColumnName 

To get the name of all DataColumns within your DataTable:

Dim name(DT.Columns.Count) As String
Dim i As Integer = 0
For Each column As DataColumn In DT.Columns
  name(i) = column.ColumnName
  i += 1
Next

References

• Data Table (MSDN)
• Data Column (MSDN)

You can loop through the columns collection of the datatable.

VB

Dim dt As New DataTable()
For Each column As DataColumn In dt.Columns
    Console.WriteLine(column.ColumnName)
Next

C#

DataTable dt = new DataTable();
foreach (DataColumn column in dt.Columns)
{
Console.WriteLine(column.ColumnName);
}

Hope this helps!

Look at

For Each c as DataColumn in dt.Columns
  '... = c.ColumnName
Next

or:

dt.GetDataTableSchema(...)

Do you have access to your database, if so just open it up and look up the column and use an SQL call to retrieve the needed.

A short example on a form to retrieve data from a database table:

Form contain only a GataGridView named DataGrid

Database name: DB.mdf

Table name: DBtable

Column names in table: Name as varchar(50), Age as int, Gender as bit.

Private Sub DatabaseTest_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
    Public ConString As String = "Data Source=.\SQLEXPRESS;AttachDbFilename=C:\Users\{username}\documents\visual studio 2010\Projects\Userapplication prototype v1.0\Userapplication prototype v1.0\Database\DB.mdf;" & "Integrated Security=True;User Instance=True"
    Dim conn As New SqlClient.SqlConnection
    Dim cmd As New SqlClient.SqlCommand
    Dim da As New SqlClient.SqlDataAdapter
    Dim dt As New DataTable
    Dim sSQL As String = String.Empty
    Try
        conn = New SqlClient.SqlConnection(ConString)
        conn.Open() 'connects to the database
        cmd.Connection = conn
        cmd.CommandType = CommandType.Text
        sSQL = "SELECT * FROM DBtable" 'Sql to be executed
        cmd.CommandText = sSQL 'makes the string a command
        da.SelectCommand = cmd 'puts the command into the sqlDataAdapter
        da.Fill(dt) 'populates the dataTable by performing the command above
        Me.DataGrid.DataSource = dt 'Updates the grid using the populated dataTable

        'the following is only if any errors happen:
        If dt.Rows.Count = 0 Then
            MsgBox("No record found!")
        End If
    Catch ex As Exception
        MsgBox(ErrorToString)
    Finally
        conn.Close() 'closes the connection again so it can be accessed by other users or programs
    End Try
End Sub

This will fetch all the rows and columns from your database table for review.
If you want to only fetch the names just change the sql call with: "SELECT Name FROM DBtable" this way the DataGridView will only show the column names.

I'm only a rookie but i would strongly advise to get rid of theses auto generate wizards. Using SQL you have full access to your database and what happens.
Also one last thing, if your database doesn't use SQLClient just change it to OleDB.

Example: "Dim conn As New SqlClient.SqlConnection" becomes: Dim conn As New OleDb.OleDbConnection

' i modify the code for Datatable 

For Each c as DataColumn in dt.Columns
 For j=0 To _dataTable.Columns.Count-1
            xlWorksheet.Cells (i+1, j+1) = _dataTable.Columns(j).ColumnName
Next
Next

Hope this could be help!