[RESOLVED] How to display item not found message box with this code?

[jcharles12]

I am trying to display a message box if the string entered in the textbox was not found in the database

Also, if the enter button is pressed and the textbox is blank, then a msgbox should say "A value must be entered"

I have tried everything to my knowledge and vb.net does not like it.

Private Sub ButtonLookup_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ButtonLookup.Click
        Try
            Dbconnect.Open()    ' Try Block - Connects To The Database. Displays An Error If It Can't.


            

            Dim DbAdapter As New MySqlDataAdapter("SELECT * FROM Itemlist WHERE Barcode = '" & TextBoxItemInput.Text & "'", Dbconnect)
            Dim DbDataSet As New DataSet
            DbAdapter.Fill(DbDataSet, "Itemlist")
            Dim DbTable As DataTable = DbDataSet.Tables("Itemlist")

      

                For Each row As DataRow In DbTable.Rows

                    Dim ItemSku As Integer = row("ItemSku").ToString()
                    Dim ItemName As String = row("ItemName").ToString()
                    Dim Barcode As String = row("Barcode").ToString()
                    Dim Price As Decimal = row("Price").ToString()

                    ItemGridView.Rows.Add(Barcode, ItemName, 1, Price, Price)
                    LabelStatus.Text = "Item Added"
                    LineDisplay.ClearText()
                    LineDisplay.DisplayText(ItemName & "    $" & Price)
                    ItemGridView.ClearSelection()
                    TextBoxItemInput.Clear()

             Next

[jmcilhinney]

Fill will return the number of records retrieve, so you simply test whether that's zero or not. By the way, why create a DataSet if all you want is a DataTable? Why not just create a DataTable?

If myDataAdapter.Fill(myDataTable) = 0 Then
    'No matching rows found.
Else
    'Yes matching rows found.
End If

[jcharles12]

What does this mean. This is coming from the next statement.
"Collection was modified; enumeration operation might not execute."

I put it at the top as well, But it is add in a dgv row twice

[jmcilhinney]

A For Each loop requires that the list that you enumerate is not altered until the loop ends.

[jcharles12]

I just remembered , that maybe I should put in an Exit For , then then it could go on to the next thing.

It seems to work fine displaying a message box for "Item Found", when I type an actual number that is in the database

But when I type an invalid item number, it never shows the message box for "Item Not Found".

[jcharles12]

I'm ok now. I just had to organize the code into the right place.

Thank you, jmcilhinney

All is well

[jmcilhinney]

Perhaps you could show us the actual code you're talking about.