Re: Filtering By Listbox

Hi Supergluey,

According to your code, Im not sure how do you want to filter the transactions by date and time. Do you want to first read the excel datatable and then filter it by your rule and finally add the result to the ListBox? If true, I think you could refer to the following demo. In the demo, first storing all CSV data to datatable and then filter it by date and time. This just provides you a method to achieve it, you could make some changes on it according to your needs.

Protected Sub btnOpenFile_Click(sender As Object, e As System.EventArgs)
	' Check file select & valid file extension
	If Me.asyncfileupload1.HasFile Then
		Try
			Dim arrFileName As [String]() = Me.asyncfileupload1.FileName.Split("."C)
			Dim filename As String = System.IO.Path.GetFileName(asyncfileupload1.PostedFile.FileName)

			Dim strTimestamp As String = DateTime.Now.ToString("yyyyMMddHHmmssfff")
			Dim currentPath As String = Server.MapPath("~/UploadsTemp/") + Path.GetFileName((Convert.ToString(arrFileName(0) + "_") & strTimestamp) + "." + arrFileName(1))

			Dim dt As New DataTable("TranTable")
			dt.Columns.AddRange(New DataColumn(2) {New DataColumn("Reader HOSTKEY", GetType([String])), New DataColumn("DATE", GetType(DateTime)), New DataColumn("CardID", GetType([String]))})
			Dim dr As DataRow = Nothing

			Dim reader As StreamReader = Nothing
			Dim line As [String] = Nothing
			Dim arrCol As [String]() = Nothing

			'asyncfileupload1.SaveAs(Server.MapPath("~/UploadsTemp/") + filename);
			Me.asyncfileupload1.SaveAs(currentPath)

			Try
				reader = New StreamReader(File.OpenRead(currentPath))
				reader.ReadLine()

				' Clear multi select box
				lbTrans.Items.Clear()

				While Not reader.EndOfStream
					line = reader.ReadLine()
					arrCol = line.Split(","C)

					dr = dt.NewRow()
					dr("Reader HOSTKEY") = arrCol(0)
					dr("DATE") = arrCol(1)
					dr("CardID") = arrCol(2)
					dt.Rows.Add(dr)
				End While
				' All log or date range is matched
				If Not rdBtnLogDateAll.Checked Then
					Dim dtBegin As DateTime = Convert.ToDateTime("2015-08-01")
					'here, you could get the value from front page
					Dim dtEnd As DateTime = Convert.ToDateTime("2015-08-31")
					'here, you could get the value from front page
					'get partial data
					Dim query = From record In dt.AsEnumerable() Where record.Field(Of DateTime)("DATE") > dtBegin AndAlso record.Field(Of DateTime)("DATE") < dtEndNew With { _
						Key .[date] = record.Field(Of DateTime)("DATE"), _
						Key .CardID = record.Field(Of String)("CardID") _
					}

					' Add to multi select box
					'selTransaction.Items.Add(New ListItem(transactionDate + ", " + arrCol(1)))
					For Each item As var In query
						lbTrans.Items.Add(New ListItem(item.date + "," + item.CardID))

					Next
				Else
					'get all data
					Dim query = From record In dt.AsEnumerable()New With { _
						Key .[date] = record.Field(Of DateTime)("DATE"), _
						Key .CardID = record.Field(Of String)("CardID") _
					}

					' Add to multi select box
					'selTransaction.Items.Add(New ListItem(transactionDate + ", " + arrCol(1)))
					For Each item As var In query
						lbTrans.Items.Add(New ListItem(item.date + "," + item.CardID))
					Next
				End If
				' Keep filename
				Session("PCRFileName") = Me.asyncfileupload1.PostedFile.FileName
			Catch ex As Exception
				Throw ex
			Finally
				reader.Close()

				dt = Nothing
				dr = Nothing

				reader = Nothing
				line = Nothing
				arrCol = Nothing
				strTimestamp = Nothing
				currentPath = Nothing

			End Try
		Catch ex As Exception
			Throw ex
		Finally
		End Try
	End If

End Sub

For more things, you could refer to the following link. It provides the explanation about how to query a datatable using Linq.

https://msdn.microsoft.com/en-us/library/bb386910(v=vs.110).aspx?cs-save-lang=1&cs-lang=vb#code-snippet-1

I hope its useful to you.

Best Regards,

Weibo Zhang