如何将crystalreportviewer与数据库连接？

Question

我有一个SQL表名Patient_Detail，我想用水晶报表填报，但错误是Object reference not set to an instance of an object.，在rd.Load("C:\Users.....

Dim dap As SqlDataAdapter 
Dim dat As DataTable 
Dim bds As BindingSource 
Dim cmd As SqlCommand 
Dim ds As DataSet 
Dim rd As ReportDocument 
Private Sub Report_Load(sender As Object, e As EventArgs) Handles MyBase.Load 

    cn.Open() 
    cmd = New SqlCommand 
    dap = New SqlAdapter 
    ds = New DataSet 
    rs = New ReportDocument 
    cmd.Connection = cn 
    cmd.CommandText = "SELECT * FROM Patient_Detail" 
    dap.SelectCommand = cmd 
    dap.Fill(ds, "Patient_Detail") 

    rd.Load("C:\Users\Hou Chandara\documents\visual studio 2013\Projects\WindowsApplication1\WindowsApplication1\MyReport.rpt") 

    rd.SetDataSource(ds) 
    CrystalReportViewer1.ReportSource = rd 
    CrystalReportViewer1.RefreshReport() 
    cn.Close() 

End Sub 

Answer 1

您需要先设置RD。 RD =新的ReportDocument（）

或声明

昏暗RD作为新的ReportDocument