VB.NET Crystal Report Viewer Locks other Forms - vb.net

Question

What will I do to allow other forms to perform while crystal report view is running?
Heres the code:
Public Sub printCurrentHistory()
If dt.Columns.Count = 0 Then
With dt
.Columns.Add("update_time")
.Columns.Add("sender")
.Columns.Add("humidity")
.Columns.Add("temperature")
.Columns.Add("rain")
.Columns.Add("wind_dir")
.Columns.Add("wind_speed")
End With
End If
For Each dr As DataGridViewRow In frmMain.dgvSearch.Rows
dt.Rows.Add(dr.Cells("Updated").Value, dr.Cells("Sender").Value, dr.Cells("Humidity").Value, dr.Cells("Temperature").Value, dr.Cells("Rain").Value, dr.Cells("Wind_Direction").Value, dr.Cells("Wind_Speed").Value)
Next
Dim rptDoc As CrystalDecisions.CrystalReports.Engine.ReportDocument
rptDoc = New CrystalReport1
rptDoc.SetDataSource(dt)
frmPrint.CrystalReportViewer1.ReportSource = rptDoc
frmPrint.ShowDialog()
dt.Rows.Clear()
dt.Clear()
dt.Dispose()
rptDoc.Dispose()
End Sub
Crystal Viewer Report Form:

Answer 1

The difference between Show and ShowDialog is that ShowDialog is application Modal meaning it prevents anything else from happening until you close it. Show on the other hand throws up the Form and continues on its way. In looking at your code I would guess that your problem is that you are disposing of rptDoc and your datasource from underneath your frmPrint. You will need to change your frmPrint to be more autonomous. I would do something like.
frmPrint = New ParentFormName(dt) 'The Form frmPrint is instantiated from
frmPrint.Show()
And then
Public Sub New( dt as DataTable)
' This call is required by the designer.
InitializeComponent()
' Add any initialization after the InitializeComponent() call.
Dim rptDoc As CrystalDecisions.CrystalReports.Engine.ReportDocument
rptDoc = New CrystalReport1
rptDoc.SetDataSource(dt)
CrystalReportViewer1.ReportSource = rptDoc
End
And in your FormClosing event dispose of your Objects then.
This is untested code I am just trying to give you a few ideas.
Another option as I stated in my Comment is to add an Event to your print form and subscribe to it in Main Form like this.
Public Class Form1
Dim frm2 As Form2
Private Sub CloseMyData()
'Dispose of your Data here
RemoveHandler frm2.myClosingEvent, AddressOf CloseMyData
End Sub
Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
frm2 = New Form2
AddHandler frm2.myClosingEvent, AddressOf CloseMyData
frm2.Show()
End Sub
End Class
Public Class Form2
Public Event myClosingEvent()
Private Sub Form2_FormClosing(sender As Object, e As System.Windows.Forms.FormClosingEventArgs) Handles Me.FormClosing
RaiseEvent myClosingEvent()
End Sub
End Class

Answer 2

Instead of
frmPrint.ShowDialog()
use
frmPrint.Show()