Pulling specific columns from a dataset. using vb.net and MySQL

Darragh-o-h

Hello,

The below code pullsfills the Content text box with the value of the PageText column using a select statement which only returns that column however if I want to extract everything from that row how do I then extract the value of the PageText column. I read somewhere that this can be done by referencing the column number. Is that right? I'm open to any suggestions. I do want to use a dataset as its not forward only. I've looked at using typed datasets but at the moment I cant find an example to learn from that's using the mysql connecter.

Any help welcome. to show how far I've got I've attached some code below.
Imports MySql.Data.MysqlClient
Imports System.Data
Imports System




Public Class WebForm1
Inherits System.Web.UI.Page

#Region " Web Form Designer Generated Code "

'This call is required by the Web Form Designer.
<System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()

End Sub
Protected WithEvents Content As System.Web.UI.WebControls.Label
'NOTE: The following placeholder declaration is required by the Web Form Designer.
'Do not delete or move it.
Private designerPlaceholderDeclaration As System.Object

Private Sub Page_Init(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Init
'CODEGEN: This method call is required by the Web Form Designer
'Do not modify it using the code editor.
InitializeComponent()
End Sub

#End Region

Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Dim DataSet As New DataSet
Dim TitleRow As DataRow
Dim TitleTable As DataTable
Dim conn As MySqlConnection
Dim DataAdapter As MySqlDataAdapter
Dim SQLCMD As String

SQLCMD = "SELECT PageText FROM Content Where ID = 1;"

Try
conn = New MySqlConnection
conn.ConnectionString = "server=localhost;" _
& "user id=User;" _
& "password=User;" _
& "database=DataBase"
DataAdapter = New MySqlDataAdapter(SQLCMD, conn)
conn.Open()
DataSet = New DataSet
DataAdapter.Fill(DataSet, "Content")
Dim CurrentTable As DataTable
Dim CurrentRow As DataRow
Dim CurrentColumn As DataColumn
For Each CurrentTable In DataSet.Tables
For Each CurrentRow In CurrentTable.Rows
For Each CurrentColumn In CurrentTable.Columns
If Not CurrentRow(CurrentColumn) Is Nothing Then
If Not IsDBNull(CurrentRow(CurrentColumn)) Then
Content.Text = Convert.ToString(CurrentRow(CurrentColumn))
Else
Content.Text = "Null"
End If
End If
Next
Next
Next
Catch myerror As MySqlException

Finally
conn.Close()
conn.Dispose()
End Try
End Sub
End Class

Mutant_Fruit

i can do it in C#, but they way i'm currently doing it in my project involves reading the data into a dataset and then referencing that dataset with a new dataview. So i end up taking whatever info i need from the dataview (who's source is the dataset).

Kernel32

Darragh-o-h wrote:

Hello,

The below code pullsfills the Content text box with the value of the PageText column using a select statement which only returns that column however if I want to extract everything from that row how do I then extract the value of the PageText column. I read somewhere that this can be done by referencing the column number. Is that right? I'm open to any suggestions. I do want to use a dataset as its not forward only. I've looked at using typed datasets but at the moment I cant find an example to learn from that's using the mysql connecter.

Datasets aren't forward only, typed or untyped. Datareader is forward only.

Never, ever, ever use an ordinal value to reference a column. Magic numbers are bad, baaaaaad.

MyDataset.Tables("tablename").Rows(rownumber)("ColumnName")

You might also want to RTFM.
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpref/html/frlrfSystemDataDataSetClassTopic.asp

Mutant_Fruit

The only time you should ever use the ordinal number is when you do something like this...

int StatusOrdinal=DataSet.Tables[0].Columns["Status"].Ordinal

That stores the ordinal number of the column "status" in the "StatusOrdinal" int. You can then safely use the ordinal number (by using the "StatusOrdinal" int) in whatever way you choose. But every time your data changes, make sure you refresh the "index" int in case the columns change position for whatever reason.