获取WebBrowser时遇到访问冲突运行时错误.Url属性

Question

当我正在写一个Outlook加载项时尝试获取WebBrowser的.Url属性时，出现“Access Violation”运行时错误。需要一些帮助，如何通过这个请。研究表明我可能需要设置“FullTrust”权限集，尝试过没有成功。

using System; 
using System.Collections.Generic; 
using System.ComponentModel; 
using System.Data; 
using System.Drawing; 
using System.Linq; 
using System.Text; 
using System.Threading.Tasks; 
using System.Windows.Forms; 
using System.Security; 
using System.Security.Permissions; 

namespace MyAddin1 
{ 

public partial class authForm : Form 
{ 

    public string currentUrl; 

    public authForm() 
    { 
     InitializeComponent(); 
    } 


    private void formLoaded(object sender, EventArgs e) 
    { 
     WebBrowser browser = new WebBrowser(); 
     browser.Location = new System.Drawing.Point(0, 0); 
     browser.Width = 870; 
     browser.Height = 510; 
     browser.Navigate("https://www.yammer.com/dialog/oauth?client_id=<redacted>&response_type=token"); 
     browser.Show(); 

     //runtime error occurs on following line 
     currentUrl = browser.Url.ToString(); 


     browser.Url = new Uri("http://www.yahoo.com"); 

     browser.Navigated += new WebBrowserNavigatedEventHandler(checkForToken); 


     this.Controls.Add(browser); 
    } 

    private void checkForToken(object sender, EventArgs e) 
    { 
     MessageBox.Show(currentUrl); 
    } 




} 

}

Answer 1

browser.Url最初为null，如下修改代码。

if (browser.Url != null) 
{ 
    currentUrl = browser.Url.ToString(); 
}