vb.net ASP.NET/VB 读取/写入 Cookies - 对象未设置为对象的实例
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ASP.NET/VB Reading/Writing Cookies - Object not set to instance of an object
提问by Billy Brown
so I have this code:
所以我有这个代码：
Try
If Request.Cookies("curUsrId")("id") Is Nothing Then
Dim cke As HttpCookie = New HttpCookie("curUsrId")
cke("id") = CStr(myUser.Id)
cke.Expires = Now.AddDays(35)
Response.Cookies.Add(cke)
Else
If Request.Cookies("curUsrId")("id") = "2" Then
grdIssues.SettingsPager.Mode = DevExpress.Web.ASPxGridView.GridViewPagerMode.ShowAllRecords
chkPaging.Checked = True
Else
grdIssues.SettingsPager.Mode = DevExpress.Web.ASPxGridView.GridViewPagerMode.ShowPager
chkPaging.Checked = False
End If
End If
Catch ex As Exception
lblErrorMsg.Visible = True
txtErrorTxt.Visible = True
txtErrorTxt.Text = ex.Message
End Try
I'm trying to read/write to a cookie, but everytime I run this, I get a "Object not set to an instance of an object" error.
我正在尝试读取/写入 cookie，但每次运行它时，都会收到“对象未设置为对象的实例”错误。
Does anyone know why?
有谁知道为什么？
I changed the code slighty, still the same error? Per the comment below, I do check to see if the value is nothing.
我稍微更改了代码，还是同样的错误？根据下面的评论，我会检查该值是否为零。
Try
If Request.Cookies("curUsrId").Value Is Nothing Then
Dim cke As HttpCookie = New HttpCookie("curUsrId")
cke.Value = CStr(myUser.Id)
cke.Expires = Now.AddDays(35)
Response.Cookies.Add(cke)
Else
If Request.Cookies("curUsrId").Value = "2" Then
grdIssues.SettingsPager.Mode = DevExpress.Web.ASPxGridView.GridViewPagerMode.ShowAllRecords
chkPaging.Checked = True
Else
grdIssues.SettingsPager.Mode = DevExpress.Web.ASPxGridView.GridViewPagerMode.ShowPager
chkPaging.Checked = False
End If
End If
Catch ex As Exception
lblErrorMsg.Visible = True
txtErrorTxt.Visible = True
txtErrorTxt.Text = ex.Message
End Try
ANOTHER EDIT:
另一个编辑：
I added a breakpoint at the Try line, guess, what it doesn't hit. "No symbol information loaded etc". I tried loading the DLL manually, I've rebuilt the solution etc, no difference?
我在 Try 行添加了一个断点，猜猜它没有命中什么。“未加载符号信息等”。我尝试手动加载 DLL，我重建了解决方案等，没有区别吗？
回答by Mairaj Ahmad
You are getting this exception because you are trying to read value of a cookie which does not exist in cookies collection.
您收到此异常是因为您正在尝试读取 cookie 集合中不存在的 cookie 值。
If Request.Cookies("curUsrId").Value //Here you are trying to read value from cookie wich is not set yet
Try this for C#
试试这个 C#
if(Request.Cookies.Get("curUsrId")==null)
{
//Your code to add cookie
}
In VB.Net
在 VB.Net 中
If Request.Cookies.Get("curUserId") Is Nothing Then
