QueryString errr:对象引用未设置为对象的实例 [英] QueryString errr: Object reference not set to an instance of an object

问题描述

大家好，

我想将gridview单元格值从一页转移到另一页.在这里，我使用了查询字符串，但震惊了它在某些字段中的工作，而在其他字段(gridview单元格值)中却无效.
我使用以下语法的具有gridview的页面:

Hello everybody,

I want to transfer gridview cells values from one page to another. Here I used query string but to shock its working for some fields and for other fields(gridview cell values) its not working.

The page which has gridview I used this syntax:

Public ReadOnly Property email() As String
      Get
          Return GridView1.SelectedRow.Cells(3).Text
      End Get
  End Property

我要使用这些值的页面，我使用了这种语法

The page where i want to use those values I used this syntax

lblemail.Text = Request.QueryString("email").ToString

Error: Object reference not set to an instance of an object

感谢您的帮助..

Thanks for your help..

推荐答案

blemail.Text = Request.QueryString("email").ToString

确保您具有名称为email的querystring参数.
这似乎为null，并将null转换为字符串会引发错误.

要消除该错误，可以使用Convert.ToString(Request.QueryString("email"));.
当您的查询字符串没有电子邮件时，这将帮助您避免错误.

但是，blemail.Text控件中将不会显示任何内容.

blemail.Text = Request.QueryString("email").ToString

Ensure that you have a querystring parameter with the name email.
This appears to be null and converting a null to a string is throwing the error.

To remove the error, you can use Convert.ToString(Request.QueryString("email"));.
This will help you avoid an error when your querystring has no email.

However, nothing will be displayed in the blemail.Text control.

grdviewLink.NavigateUrl +="&email=" + Me.GridView1.SelectedRow.Cells(3).Text

添加字段以浏览URL ...

Add the field to navigate URL...

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