Here it is: Code for an Incremental Search Grid in VB .NET

I got so frustrated trying to find an Incremental Search Grid in VB .NET that it drove me to finally write the code myself. I got a hint of how to do it from Kenvin Goff here in the Universal Thread Mere Mortals section, but it was in C, and I'm a VB programmer; but I finally figured it out, and I finally got to do it in VB .NET. I'm not a real experienced VB .NET programmer so there may be a lot of redundant code in here, and I might not know completely what I'm talking about, but the thing does work.

First I have a tab screen (Find Records) that has some labels, text boxes, buttons and a grid on it. Here are the important ones:
txtReqNum2, txtPO_Num, txtCompany
grdReqs bound to Requisitions business object.

I use stored procedures to get the records, and only for the currently logged in user.

Here's the code:
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Private Sub txtReqNum2_GotFocus(ByVal sender As Object, ByVal e As System.EventArgs) Handles txtReqNum2.GotFocus
Me.dsReqs = Me.oRequisitions.GetReqsForUserSP(gcUser)
ClearControls()
End Sub

Private Sub txtPO_Num_GotFocus(ByVal sender As Object, ByVal e As System.EventArgs) Handles txtPO_Num.GotFocus
Me.dsReqs = Me.oRequisitions.GetReqsForUserPOSortSP(gcUser)
ClearControls()
End Sub

Private Sub txtCompany_GotFocus(ByVal sender As Object, ByVal e As System.EventArgs) Handles txtCompany.GotFocus
Me.dsReqs = Me.oRequisitions.GetReqsForUserCompSortSP(gcUser)
ClearControls()
End Sub

Private Sub txtReqNum2_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles txtReqNum2.TextChanged
Dim lcStr As String
lcStr = UCase(Trim(Me.txtReqNum2.Text().ToString))
IncrSearch(lcStr, "ReqID")
End Sub

Private Sub txtPO_Num_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles txtPO_Num.TextChanged
Dim lcStr As String
lcStr = UCase(Trim(Me.txtPO_Num.Text().ToString))
IncrSearch(lcStr, "PONum")
End Sub

Private Sub txtCompany_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles txtCompany.TextChanged
Dim lcStr As String
lcStr = UCase(Trim(Me.txtCompany.Text().ToString))
IncrSearch(lcStr, "Company")
End Sub

Private Sub IncrSearch(ByVal lcStr, ByVal lcSortOrder)
'Get the Default View of the DataSet
Dim ds As DataSet = Me.oRequisitions.GetCurrentDataSet()
ds.Tables(0).DefaultView.Sort = lcSortOrder

'Set up the local search variables
Dim i, lnRowCount, lnSize As Integer
Dim lcField, lcSrchTerm, lcReqID As String
Dim bMgr = Me.BindingContext(grdReqs.DataSource, grdReqs.DataMember)
lnRowCount = Me.oRequisitions.GetRowCount
lnSize = Len(lcStr)

'Start searching for the lcField value
For i = 0 To lnRowCount - 1
'Get the field value for the row
lcField = UCase(ds.Tables(0).DefaultView(i)(lcSortOrder))
lcSrchTerm = Microsoft.VisualBasic.Left(lcField, lnSize)
If lcSrchTerm = lcStr Then
Dim Position As Integer = ds.Tables(0).DefaultView.Find(lcField)
Me.BindingContext(dsReqs, dsReqs.Tables(0).TableName).Position = Position
bMgr.position = Position
Exit For
End If
Next

End Sub

Private Sub ClearControls()
Me.txtReqNum2.Text = ""
Me.txtPO_Num.Text = ""
Me.txtCompany.Text = ""
End Sub

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Here's the way it works:
When a text box gets the focus it sets the sort of the data set so that the grid column is displayed in the correct sort order, and then clears out the text boxes:

Me.dsReqs = Me.oRequisitions.GetReqsForUserCompSortSP(gcUser)
ClearControls()

Then when the text changes, it formats the search string and calls the IncrSearch function with the search string and to set the sort order for the search.

Dim lcStr As String
lcStr = UCase(Trim(Me.txtCompany.Text().ToString))
IncrSearch(lcStr, "Company")

The incremental search function then makes sure the Default View is in the correct sort order. It then sets up the local search variables and binds the grid to the data set.

It then looks through the records, first to get the actual field value, then for the first letter of the search string we are looking for, and if it finds a match, will get it's position, makes sure the grid is pointing to it, and then jumps out of the loop, ready to get the next letter. (Warning, this code doesn't like Nulls in the fields, so for now I just make sure there isn't any in my tables.)

That's it. I hope this will help you all out.

CU