我在将数据从datatable传递到子报表时遇到了麻烦，我总是得到一个错误
Object reference not set to an instance of an object.
我是水晶报告的新手，我正在使用vb.Net使用visual studio 2012.希望你能帮助我谢谢你:)
Private Sub Button4_Click（sender As Object，e As EventArgs）处理Button4.Click
Try
Dim frm As New Printform
Dim rpt As New mainreport
Dim dt1 As New DataTable
Dim dt2 As New DataTable
Dim dt3 As New DataTable
Dim dt4 As New DataTable
Dim dt5 As New DataTable
With dt1.Columns
.Add("Date")
.Add("Attended By")
.Add("Last name")
.Add("First name")
.Add("Initial")
.Add("Street")
.Add("City")
.Add("Zipcode")
.Add("Dob")
.Add("Age")
.Add("Height")
.Add("Weight")
.Add("Gender")
.Add("Status")
.Add("Number")
.Add("Type")
End With
With dt2.Columns
.Add("Attended By")
.Add("Patient")
.Add("Patient Type")
.Add("Date")
.Add("Complaints")
.Add("Type")
.Add("Medicine")
.Add("Quantity")
.Add("Remarks")
End With
With dt3.Columns
.Add("Attended By")
.Add("Patient")
.Add("Type")
.Add("Date")
.Add("rep")
.Add("flo")
.Add("lun")
.Add("hea")
.Add("sys")
.Add("dia")
.Add("pul")
.Add("sit")
.Add("agi")
.Add("dig")
.Add("gen")
.Add("uri")
.Add("ski")
.Add("loc")
.Add("ner")
.Add("eye")
.Add("col")
.Add("vis")
.Add("far")
.Add("fal")
.Add("ear")
.Add("hear")
.Add("nose")
.Add("thro")
.Add("rema")
.Add("reco")
End With
With dt4.Columns
.Add("Attended By")
.Add("Patient")
.Add("Type")
.Add("Date")
.Add("phy")
.Add("hea")
.Add("hig")
.Add("low")
.Add("cir")
.Add("ner")
.Add("rad")
.Add("exc")
.Add("ane")
.Add("sin")
.Add("dia")
.Add("epi")
.Add("mal")
.Add("rhe")
.Add("thy")
.Add("tub")
.Add("hep")
.Add("ven")
.Add("chi")
.Add("his")
.Add("cli")
.Add("xray")
.Add("diag")
.Add("trea")
.Add("t1")
.Add("t2")
.Add("t3")
.Add("t4")
.Add("t5")
.Add("t6")
.Add("t7")
.Add("t8")
.Add("t9")
.Add("t10")
.Add("t11")
.Add("t12")
.Add("t13")
.Add("t14")
.Add("t15")
.Add("t16")
.Add("t17")
.Add("t18")
.Add("t19")
.Add("t20")
.Add("t21")
.Add("t22")
.Add("t23")
.Add("t24")
.Add("t25")
.Add("t26")
.Add("t27")
.Add("t28")
.Add("t29")
.Add("t30")
.Add("t31")
.Add("t32")
End With
With dt5.Columns
.Add("name")
.Add("immu")
.Add("alle")
.Add("prob")
End With
For i As Integer = 0 To frmviewallrecords.dv1.RowCount - 1
dt1.Rows.Add(frmviewallrecords.dv1.Rows(i).Cells(0).Value, frmviewallrecords.dv1.Rows(i).Cells(2).Value, frmviewallrecords.dv1.Rows(i).Cells(3).Value, frmviewallrecords.dv1.Rows(i).Cells(4).Value, frmviewallrecords.dv1.Rows(i).Cells(5).Value, _
frmviewallrecords.dv1.Rows(i).Cells(6).Value, frmviewallrecords.dv1.Rows(i).Cells(7).Value, frmviewallrecords.dv1.Rows(i).Cells(8).Value, frmviewallrecords.dv1.Rows(i).Cells(9).Value, frmviewallrecords.dv1.Rows(i).Cells(10).Value, _
frmviewallrecords.dv1.Rows(i).Cells(11).Value, frmviewallrecords.dv1.Rows(i).Cells(12).Value, frmviewallrecords.dv1.Rows(i).Cells(13).Value, frmviewallrecords.dv1.Rows(i).Cells(14).Value, _
frmviewallrecords.dv1.Rows(i).Cells(15).Value, frmviewallrecords.dv1.Rows(i).Cells(16).Value)
Next
For i As Integer = 0 To frmviewallrecords.dv2.RowCount - 1
dt2.Rows.Add(frmviewallrecords.dv2.Rows(i).Cells(2).Value, frmviewallrecords.dv2.Rows(i).Cells(3).Value, frmviewallrecords.dv2.Rows(i).Cells(4).Value, _
frmviewallrecords.dv2.Rows(i).Cells(5).Value, frmviewallrecords.dv2.Rows(i).Cells(6).Value, frmviewallrecords.dv2.Rows(i).Cells(7).Value, _
frmviewallrecords.dv2.Rows(i).Cells(8).Value, frmviewallrecords.dv2.Rows(i).Cells(9).Value, frmviewallrecords.dv2.Rows(i).Cells(10).Value)
Next
For i As Integer = 0 To frmviewallrecords.dv3.RowCount - 1
dt3.Rows.Add(frmviewallrecords.dv3.Rows(i).Cells(2).Value, frmviewallrecords.dv3.Rows(i).Cells(3).Value, frmviewallrecords.dv3.Rows(i).Cells(4).Value, frmviewallrecords.dv3.Rows(i).Cells(7).Value, frmviewallrecords.dv3.Rows(i).Cells(8).Value, _
frmviewallrecords.dv3.Rows(i).Cells(9).Value, frmviewallrecords.dv3.Rows(i).Cells(10).Value, frmviewallrecords.dv3.Rows(i).Cells(11).Value, frmviewallrecords.dv3.Rows(i).Cells(12).Value, frmviewallrecords.dv3.Rows(i).Cells(13).Value, _
frmviewallrecords.dv3.Rows(i).Cells(14).Value, frmviewallrecords.dv3.Rows(i).Cells(15).Value, frmviewallrecords.dv3.Rows(i).Cells(16).Value, frmviewallrecords.dv3.Rows(i).Cells(17).Value, frmviewallrecords.dv3.Rows(i).Cells(18).Value, _
frmviewallrecords.dv3.Rows(i).Cells(19).Value, frmviewallrecords.dv3.Rows(i).Cells(20).Value, frmviewallrecords.dv3.Rows(i).Cells(21).Value, frmviewallrecords.dv3.Rows(i).Cells(22).Value, frmviewallrecords.dv3.Rows(i).Cells(23).Value, _
frmviewallrecords.dv3.Rows(i).Cells(24).Value, frmviewallrecords.dv3.Rows(i).Cells(25).Value, frmviewallrecords.dv3.Rows(i).Cells(26).Value, frmviewallrecords.dv3.Rows(i).Cells(27).Value, frmviewallrecords.dv3.Rows(i).Cells(28).Value, _
frmviewallrecords.dv3.Rows(i).Cells(29).Value, frmviewallrecords.dv3.Rows(i).Cells(30).Value, frmviewallrecords.dv3.Rows(i).Cells(31).Value, frmviewallrecords.dv3.Rows(i).Cells(32).Value, frmviewallrecords.dv3.Rows(i).Cells(33).Value)
Next
For i As Integer = 0 To frmviewallrecords.dv4.RowCount - 1
dt4.Rows.Add(frmviewallrecords.dv4.Rows(i).Cells(2).Value, frmviewallrecords.dv4.Rows(i).Cells(3).Value, frmviewallrecords.dv4.Rows(i).Cells(4).Value, frmviewallrecords.dv4.Rows(i).Cells(7).Value, frmviewallrecords.dv4.Rows(i).Cells(8).Value, _
frmviewallrecords.dv4.Rows(i).Cells(9).Value, frmviewallrecords.dv4.Rows(i).Cells(10).Value, frmviewallrecords.dv4.Rows(i).Cells(11).Value, frmviewallrecords.dv4.Rows(i).Cells(12).Value, frmviewallrecords.dv4.Rows(i).Cells(13).Value, _
frmviewallrecords.dv4.Rows(i).Cells(14).Value, frmviewallrecords.dv4.Rows(i).Cells(15).Value, frmviewallrecords.dv4.Rows(i).Cells(16).Value, frmviewallrecords.dv4.Rows(i).Cells(17).Value, frmviewallrecords.dv4.Rows(i).Cells(18).Value, _
frmviewallrecords.dv4.Rows(i).Cells(19).Value, frmviewallrecords.dv4.Rows(i).Cells(20).Value, frmviewallrecords.dv4.Rows(i).Cells(21).Value, frmviewallrecords.dv4.Rows(i).Cells(22).Value, frmviewallrecords.dv4.Rows(i).Cells(23).Value, _
frmviewallrecords.dv4.Rows(i).Cells(24).Value, frmviewallrecords.dv4.Rows(i).Cells(25).Value, frmviewallrecords.dv4.Rows(i).Cells(26).Value, frmviewallrecords.dv4.Rows(i).Cells(27).Value, frmviewallrecords.dv4.Rows(i).Cells(28).Value, _
frmviewallrecords.dv4.Rows(i).Cells(29).Value, frmviewallrecords.dv4.Rows(i).Cells(30).Value, frmviewallrecords.dv4.Rows(i).Cells(31).Value, frmviewallrecords.dv4.Rows(i).Cells(32).Value, frmviewallrecords.dv4.Rows(i).Cells(33).Value, _
frmviewallrecords.dv4.Rows(i).Cells(34).Value, frmviewallrecords.dv4.Rows(i).Cells(35).Value, frmviewallrecords.dv4.Rows(i).Cells(36).Value, frmviewallrecords.dv4.Rows(i).Cells(37).Value, frmviewallrecords.dv4.Rows(i).Cells(38).Value, _
frmviewallrecords.dv4.Rows(i).Cells(39).Value, frmviewallrecords.dv4.Rows(i).Cells(40).Value, frmviewallrecords.dv4.Rows(i).Cells(41).Value, frmviewallrecords.dv4.Rows(i).Cells(42).Value, frmviewallrecords.dv4.Rows(i).Cells(43).Value, _
frmviewallrecords.dv4.Rows(i).Cells(44).Value, frmviewallrecords.dv4.Rows(i).Cells(45).Value, frmviewallrecords.dv4.Rows(i).Cells(46).Value, frmviewallrecords.dv4.Rows(i).Cells(47).Value, frmviewallrecords.dv4.Rows(i).Cells(48).Value, _
frmviewallrecords.dv4.Rows(i).Cells(49).Value, frmviewallrecords.dv4.Rows(i).Cells(50).Value, frmviewallrecords.dv4.Rows(i).Cells(51).Value, frmviewallrecords.dv4.Rows(i).Cells(52).Value, frmviewallrecords.dv4.Rows(i).Cells(53).Value, _
frmviewallrecords.dv4.Rows(i).Cells(54).Value, frmviewallrecords.dv4.Rows(i).Cells(55).Value, frmviewallrecords.dv4.Rows(i).Cells(56).Value, frmviewallrecords.dv4.Rows(i).Cells(57).Value, frmviewallrecords.dv4.Rows(i).Cells(58).Value, _
frmviewallrecords.dv4.Rows(i).Cells(59).Value, frmviewallrecords.dv4.Rows(i).Cells(60).Value, frmviewallrecords.dv4.Rows(i).Cells(61).Value, frmviewallrecords.dv4.Rows(i).Cells(62).Value, frmviewallrecords.dv4.Rows(i).Cells(63).Value)
Next
Dim count As Integer = frmviewallrecords.dv5.RowCount
If frmviewallrecords.dv6.RowCount > frmviewallrecords.dv5.RowCount Then
count = frmviewallrecords.dv6.RowCount
If frmviewallrecords.dv7.RowCount > frmviewallrecords.dv6.RowCount Then
count = frmviewallrecords.dv7.RowCount
End If
ElseIf frmviewallrecords.dv7.RowCount > frmviewallrecords.dv5.RowCount Then
count = frmviewallrecords.dv7.RowCount
End If
For i As Integer = 0 To count - 1
Dim immu As String
Dim alle As String
Dim prob As String
immu = getImmu(frmviewallrecords.dv5, i)
alle = getAlle(frmviewallrecords.dv6, i)
prob = getProb(frmviewallrecords.dv7, i)
dt5.Rows.Add(frmviewallrecords.Label8.Text, immu, alle, prob)
Next
rpt.Subreports.Item("Subreport1").SetDataSource(dt1)--------->Error: Object reference not set to an instance of an object
rpt.Subreports.Item("Subreport2").SetDataSource(dt2)
rpt.Subreports.Item("Subreport3").SetDataSource(dt3)
rpt.Subreports.Item("Subreport4").SetDataSource(dt4)
rpt.Subreports.Item("Subreport5").SetDataSource(dt5)
With frm
frm.CrystalReportViewer1.ReportSource = rpt
frm.ShowDialog()
End With
Catch ex As Exception
MsgBox(ex.Message)
End Try
End Sub