C#和VB.NET LDAP搜索不同？

Question

有谁知道C#和VB.NET中DirectorySearcher对象上的FindAll()方法的实现是否有区别？根据我的理解,它们都被"编译"到MSIL并由CLR以相同的方式处理.与我们的ADAM/LDAP系统相反,下面的C#代码会抛出错误,而下面的VB.NET则不会.

这是C#异常堆栈:

at System.DirectoryServices.DirectoryEntry.Bind(Boolean throwIfFail)
  at System.DirectoryServices.DirectoryEntry.Bind()
  at System.DirectoryServices.DirectoryEntry.get_AdsObject()
  at System.DirectoryServices.DirectorySearcher.FindAll(Boolean findMoreThanOne)
  at System.DirectoryServices.DirectorySearcher.FindAll()

这是C#错误:

System.Runtime.InteropServices.COMException was unhandled
Message="The parameter is incorrect.\r\n"
Source="System.DirectoryServices"
ErrorCode=-2147024809

C#代码:

private void button1_Click(object sender, EventArgs e)
{
    DirectoryEntry root = new DirectoryEntry("LDAP://directory.corp.com/OU=Person,OU=Lookups,O=Corp,C=US", null, null, AuthenticationTypes.Anonymous);
    DirectorySearcher mySearcher = new DirectorySearcher(root);

    mySearcher.Filter = "(uid=ssnlxxx)";
    mySearcher.PropertiesToLoad.Add("cn");
    mySearcher.PropertiesToLoad.Add("mail");

    SearchResultCollection searchResultCollection = null;
    searchResultCollection = mySearcher.FindAll(); //this is where the error occurs

    try
    {
        foreach (SearchResult resEnt in searchResultCollection)
        {
            Console.Write(resEnt.Properties["cn"][0].ToString());
            Console.Write(resEnt.Properties["mail"][0].ToString());
        }
    }
    catch (DirectoryServicesCOMException ex)
    {
        MessageBox.Show("Failed to connect LDAP domain, Check username or password to get user details.");
    }
}

这是有效的VB.NET代码:

Private Sub Button1_Click(ByVal sender As Object, ByVal e As EventArgs) Handles Button1.Click

    Dim root As New     DirectoryEntry("LDAP://directory.corp.com/OU=People,OU=Lookups,O=corp,C=US", vbNull, vbNull, authenticationType:=DirectoryServices.AuthenticationTypes.Anonymous)
    Dim searcher As New DirectorySearcher(root)
    searcher.Filter = "(uid=ssnlxxx)"
    searcher.PropertiesToLoad.Add("cn")
    searcher.PropertiesToLoad.Add("mail")

    Dim results As SearchResultCollection

    Try
        results = searcher.FindAll()

        Dim result As SearchResult
        For Each result In results
            Console.WriteLine(result.Properties("cn")(0))
            Console.WriteLine(result.Properties("mail")(0))
        Next result
    Catch ex As Exception
        MessageBox.Show("There was an error")
    End Try
End Sub

Answer 1

我猜想在VB.NET代码中,你是在构造函数中传入vbNull(代替Nothing)两个参数DirectoryEntry,而在传递的C#代码中传递null.vbNull大概来自Microsoft.VisualBasic不应该使用的邪恶集会.

用于DirectoryEntry检查用户名和密码参数的构造函数,以查看它们是否为空.如果vbNull != Nothing,构造函数不会将它们视为null并且行为方式不同.

查看VB.NET代码是否在您使用时抛出异常Nothing,或者通过使用String.Empty而不是查看C#代码是否有效null.

此外,在您的C#代码中,调用FindAll是在try块之外.

Answer 2

C# 和 VB.NET 都不实现DirectorySearcher.NET 或任何其他部分。它们都是 .NET Framework 的一部分。