大家帮我看下有什么错误， Dim readstr As New IO.StreamReader(adstr, Encoding.Default)

[Rose童鞋]

我的代码是这样的，我在做博客网页，这个代码是查看日志用的。。
Imports System.Data
Imports System.Data.SqlClient


Partial Class 查看日志
Inherits System.Web.UI.Page
Dim conn As New SqlConnection("Data Source=.\SQLEXPRESS;AttachDbFilename=" & Server.MapPath("App_Data/blogdata_Data.mdf") & ";Integrated Security=True;User Instance=True")


Dim ds As New DataSet

Dim sqlname As String
Dim wenname As String
Dim bsqlname As String


Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
Dim sqlstr As String
Dim adstr As String
Dim i As Integer
Dim fenxin As String
Dim fenstr As String
Dim count As Integer
Dim fir As Integer
Dim sec As Integer
Dim namestr As String
Dim timestr As String
Dim min As Integer
i = 1
Dim str As String
str = Session("Busername")
If str = "" Then
sqlname = Session("Ausername")
bsqlname = Session("Ausername")
uname.Text = sqlname
Else
If str <> Session("Ausername") Then
sqlname = str
bsqlname = Session("Ausername")
uname.Text = bsqlname
h1.Visible = False
li1.Visible = False
li2.Visible = False
li3.Visible = False
ElseIf str = Session("Ausername") Then
sqlname = str
bsqlname = sqlname
uname.Text = bsqlname
End If
End If
wenname = Request.QueryString("wenname")
If Not IsPostBack Then
If sqlname <> "" Then

sqlstr = "select * from " & sqlname & "wen where 文章='" & wenname & "'"
Dim cmd As New SqlCommand(sqlstr, conn)
conn.Open()
Dim dr As SqlDataReader = cmd.ExecuteReader
Do While dr.Read
time.Text = dr.Item("日期")
adstr = Server.MapPath(dr.Item("地址"))
leibie.Text = dr.Item("类别")
Try
count = dr.Item("评论数")
Catch ex As Exception

End Try

Loop
conn.Close()
If count < 1 Then
lbpinglun.Text = "<p style='margin-left:270px;margin-top:75px; color:red;'>此文章还没有评论，赶快来评论！</p>"
Else
conn.Open()
Dim drr As SqlDataReader = cmd.ExecuteReader
Do While drr.Read
For i = 1 To count
fenstr = "评论" & i
fenstr = drr.Item(fenstr)
fir = fenstr.IndexOf("$")
sec = fenstr.LastIndexOf("#")
namestr = fenstr.Substring(fir + 1, sec - fir - 1)
timestr = fenstr.Substring(sec + 1)
fenstr = fenstr.Substring(0, fir)
lbpinglun.Text += "<div style='width:100%; height :112px;'><p style='width :100%; height :80px; text-indent :5em; color:blue;'> " & fenstr & "</p>"
lbpinglun.Text += " <p style ='float :right ; font-size :small ;'>评论人：" & namestr & "<br/>" & timestr & "</p> </div><hr/>"

Next
Loop

End If


title.Text = wenname
Dim readstr As New IO.StreamReader(adstr, Encoding.Default)

Do While readstr.Peek > -1
wenbox.Text &= readstr.ReadLine
wenbox.Text &= "<br/>"
Loop
readstr.Close()
End If
End If
End Sub
然后可以运行，但是点击查看日志的时候，指向readstr As New IO.StreamReader(adstr, Encoding.Default)这句，然后提示：


值不能为空。
参数名: path

[孟子E章]

打印出 adstr看是什么

[Rose童鞋]

还有说找不到路径，也是同一句。。

[vrhero]

dr.Item("地址")有空值，加判断...

ps:VB代码这么看起来好乱...

[vrhero]

[Quote=引用 2 楼 xiayuqiuyu520 的回复:]
还有说找不到路径，也是同一句。。
[/Quote]
那就是没路径...确保你这个dr.Item("地址")里的值不为null且有对应的物理路径...

如果有null加判断过滤，如果没有物理路径加判断创建...你不是第一天写程序吧...

[wuyq11]

file.exists判断文件是否存在
F11单步查看值

[Rose童鞋]

[Quote=引用 4 楼 vrhero 的回复:]
引用 2 楼 xiayuqiuyu520 的回复:
还有说找不到路径，也是同一句。。

那就是没路径...确保你这个dr.Item("地址")里的值不为null且有对应的物理路径...

如果有null加判断过滤，如果没有物理路径加判断创建...你不是第一天写程序吧...
[/Quote]

这个问题不大，是我不小心删了一个文件夹，主要还是：值不能为空。
参数名: path