如何创建返回arraylist rom sql server的web服务asmx [英] how create web service asmx who return arraylist rom sql server

问题描述

我需要帮助

i想创建一个从sql server返回arraylist的web服务asmx！

i有错误System.NullReferenceException：la reference de l'objet n'est pas definie une instance de l'objet

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I need a help
i would like create an web service asmx who return arraylist from sql server !
i have an error System.NullReferenceException: la reference de l'objet n'est pas definie une instance de l'objet
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<webmethod()> _
Public Function data() As ArrayList()
Dim con As New SqlConnection
con.ConnectionString = "Data Source=.;Initial Catalog=personnel;Integrated Security=True"
con.Open()
Dim Sql As String = "select Nom from Employes "
Sql = String.Format(Sql)
Dim Command As New SqlCommand(Sql, con)
Dim dr As SqlDataReader
dr = Command.ExecuteReader()
'Dim result = ""
While dr.Read()
result.Add(dr(0).ToString)
Return result.ToArray
End While
Return result.ToArray
Dim sas As String
Dim x As New web_servive_array.Web
sas = x.data(Sql).ToString
con.Close()
Return result.ToArray
End Function

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请帮助

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please help

推荐答案

首先它是VB.Net代码，所以从你的问题中删除C＃标签:)。

那里抛出的异常尝试取消引用空对象引用。

有关详细信息，请参阅： https://msdn.microsoft.com/en-us/library/system.nullreferenceexception%28v=vs.110%29.aspx [ ^ ]

尝试调试代码，如果指定出现此错误的哪一行会更好。

Hi, First of all it's VB.Net code so remove C# tag from your question :).
The exception that is thrown when there is an attempt to dereference a null object reference.
For more information see this : https://msdn.microsoft.com/en-us/library/system.nullreferenceexception%28v=vs.110%29.aspx[^]
Try to debug your code and it will be better if you specify on which line you are getting this error.

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