Get specific row value from DataTable

Get specific row value from DataTable

• Riven

  Sure makes things simpler, I'd had a complete brain freeze there.

  The x-1 is because the rows is a zero based collection and I'm using a 1 based index. So when I want first item it will get element 0. Thats just my implementation - you could keep it all zero based if you want to.

  ''' <summary>
  ''' Return a field at a specific ordinal row in a datatable
  ''' </summary>
  ''' <param name="x"></param>
  ''' <param name="dt"></param>
  ''' <param name="Field"></param>
  ''' <returns></returns>
  ''' <remarks></remarks>
  Function GetSpecificRow(ByVal x As Integer, ByVal dt As DataTable, ByVal Field As String) As Object
  Try
  Return dt.Rows(x - 1).Item(Field)
  Catch ex As Exception
  Throw New Exception("Invalid Row")
  End Try
  End Function

  
  

• catz

  Hi there.

  What are you using the dataset for.

  To reference a particular row for a table its

  Table.row(rownumber).item(itemnumber)

  I'm really rusty on datasets but I think it's like this:

  Dataset.Table(tablenumber).row(rownumber).item(itemnumber)

  The number can also be strings resprenting names but my guess is that would be a little slower than indexes.

  
  
  

• Manic_Again

  And....

  The table has more than 100 rows. What issue does that cause - tables can have millions of rows depending upon your database.

  
  

• Andrea Williams

  Hey there, I got the answer thanks for all you Help!!, the code is something like this:

  For Each Table as DataTable in DataTableCollection.Tables

  Dim GenericValue as Integer = CInt(Int(Table.Rows.Count * Rnd()))

  MsgBox(cType(Table.Rows(GenericValue).Item(0), Object).toString)

  Next

  Thanks for all !!! :D

  
  

• Jeeves

  Hey there, I got your point then have another problem, the tables has more than 100 rows!!

  
  

• RickHalliday

  Hey there, thanks for the reply, I used your code before but the problem is that I'm trying to convert it to string and it shows an error, the tables I'm using done have a key column so I can't get the row using the

  datatable.rows.find(

  so I have to get the value from the row with other method, all the tables has the same columnName and the tablesname are deferent, the the within the tables are simple strings, so I need to get a ramdon row for each table, I hope this helps, I have tried everything and anything works!!. thanks!!.

  the other way is creating a column key that I think is easier and then just apply the find method but I don't know how to create it.

  
  

• Mahesh_MVP

  Hey there, how can I create an autonumeric column in a database

  I know it's like

  DataTable.Columns.Add("ColumnName", "and here the type")

  is there any type that I could use for an autonumeric one

  thanks!!.

  
  

• Alvin Kuiper

  I got your point, and it's pretty helpfull but my problem is now that I need to convert the value to a string cause I need the text witthin the field selected

  thanks

  
  

• Giampaolo

  Ccercone

  I can't tell who you are asking...

  
  
  

• Tim Noonan

  Can you be a bit more specific about what these tables are containing.

  How are you intending to identify the specific row to get the value. Does it have an Unique ID in a specific field .

  Are all the tables the same

  If your simply talking about an ordinal position row then the following sample might work or give you an idea. The function is in bold and will return and object but you can modify this to return back the specific dataType.

  Public Class Form1
  Dim dt As New DataTable
  Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

  dt.Columns.Add("ID")
  dt.Rows.Add(1)
  dt.Rows.Add(2)
  dt.Rows.Add(19)
  dt.Rows.Add(4)
  dt.Rows.Add(5)
  dt.Rows.Add(99)
  End Sub

  Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
  MsgBox(CType(GetSpecificRow(3, dt, "ID"), Integer).ToString)
  MsgBox(CType(GetSpecificRow(6, dt, "ID"), Integer).ToString)

  MsgBox(CType(GetSpecificRow(100, dt, "ID"), Integer).ToString)

  End Sub

  ''' <summary>
  ''' Return a field at a specific ordinal row in a datatable
  ''' </summary>
  ''' <param name="x"></param>
  ''' <param name="dt"></param>
  ''' <param name="Field"></param>
  ''' <returns></returns>
  ''' <remarks></remarks>
  Function GetSpecificRow(ByVal x As Integer, ByVal dt As DataTable, ByVal Field As String) As Object
  Dim i As Integer = 1
  For Each obj As Object In dt.Rows
  If i = x Then
  Return obj(Field)
  End If
  i = i + 1
  Next
  Throw New Exception("Invalid Row")
  End Function
  End Class

  
  

• TrickyToo

  OK this ones a completely different issue. I would suggest creating a separate post for this issue so as to not confuse issues and to make the title relevent to the actual post.

  
  

• tjbk23

  So your telling me your using strings.  I've changed the column so that its storing string and returns a string - so you get a random integer number and then use this in the call to the method.   This requires no use of find method and would simply retrieve the string on the row that you request.

   

  Public Class Form1
      Dim dt As New DataTable
      Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

          dt.Columns.Add("ID")
          dt.Rows.Add("test1")
          dt.Rows.Add("test2")
          dt.Rows.Add("testabc")
          dt.Rows.Add("4")
          dt.Rows.Add("item5")
          dt.Rows.Add("item 6 but show 99")
      End Sub

      Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
          MsgBox(GetSpecificRow(1, dt, "ID").ToString) '1st value
          MsgBox(GetSpecificRow(4, dt, "ID").ToString) '4th value

          'MsgBox(GetSpecificRow(100, dt, "ID").ToString) '//Intentional Exception

      End Sub

  ''' <summary>
  ''' Return a field at a specific ordinal row in a datatable
  ''' </summary>
  ''' <param name="x"></param>
  ''' <param name="dt"></param>
  ''' <param name="Field"></param>
  ''' <returns></returns>
  ''' <remarks></remarks>
      Function GetSpecificRow(ByVal x As Integer, ByVal dt As DataTable, ByVal Field As String) As String
          Try
              Return dt.Rows(x - 1).Item(Field)
          Catch ex As Exception
              Throw New Exception("Invalid Row")
          End Try
      End Function
  End Class

  
  

• Karthik Krishnaswami

  The examples show one which uses string and the value returned are strings. The original intention with using Object was I could return any data from any field type as and object and cast it to an appropriate type when it was returned from the function.

  
  
• Get specific row value from DataTable