vb.net – ‘[Modulename]’的类型初始值设定项引发异常

我有这个新的vb.net项目(MedicalCost)有这个错误“’MedicalCost.Constants’的类型初始化程序引发了异常.”在运行sub时我已经在我之前的项目中完成了这一切,当我在我的模块上声明公共变量但现在在我当前的项目中它不起作用时一切正常.

这是我模块上的代码(常量)：

Imports System.Data.Sql
    Imports System.Data.SqlClient
    Imports System.Data.Odbc
    Imports System.Windows.Forms

    Public Module Constants
        Public ppiconn As New SqlConnection("Dsn=pandiman2002connectdsn;server=ppi;uid=sa;database=Pandimandata2002")
        'Dsn=pandiman2002connectdsn;description=PPI Database;uid=sa;app=Microsoft? Visual Studio? 2010;wsid=CRWUSER17-PC;database=Pandimandata2002
        Public da As New SqlDataAdapter
        Public comm As New SqlCommand
        Public dr As SqlDataReader
        Public ds As New DataSet

        Public x As String


    End Module

当我在我的frm_add上运行sub时

这是我的代码

Sub search_crew()

    Try
        x = "(isnull(ltrim(rtrim(firstname)),'') + ' ' + isnull(ltrim(rtrim(mi)),'') + ' ' + " _
               & "isnull(ltrim(rtrim(lastname)),'') like '%" & Replace(searchbox.Text," ","%") & "%' " _
               & " or isnull(ltrim(rtrim(lastname)),'') + ' ' + " _
               & "isnull(ltrim(rtrim(firstname)),"%") & "%' " _
               & "or legal_records.caseno like '%" & UCase(searchbox.Text) & "%')"

        ppiconn.Close()
        ppiconn.Open()
        Pandimandata2002DataSet.EnforceConstraints = False
        da = New SqlDataAdapter(select_tblcrw & "where " & x,ppiconn)
        da.Fill(Pandimandata2002DataSet.tblCrew)
        da.Dispose()
        ppiconn.Close()
    Catch ex As Exception
        MsgBox(ex.Message)
    End Try

End Sub

我注意到从模块声明的任何变量都是这个错误“’MedicalCost.Constants’的类型初始化器引发异常的原因.”发生.

谁能帮我.我花了1个小时搜索这个错误,并没有帮助我.
TNX！

Public ppiconn As New SqlConnection("Dsn=pandiman2002connectdsn;server=ppi;uid=sa;database=Pandimandata2002")