的NullReferenceException实例化对象？ [英] NullReferenceException on instanciated object?

问题描述

这是从我所继承的应用程序code的一个片段，用户有死亡的黄色画面：

  

对象引用不设置到对象的实例

就行了：

 布尔l_Success ...
 

现在我95％肯定有问题的说法是 REF l_Monitor 这是非常奇怪的考虑对象实例化前几行。任何人都有一个线索，为什么会发生这种事？请注意，我已经看到了同样的问题在code等地流行起来。

  IDMS.Monitor l_Monitor =新IDMS.Monitor（）;
l_Monitor.LogFile.Product_ID =SE_WEB_APP;如果（m_PermType_RadioButtonList.SelectedIndex == -1）{
    l_Monitor.LogFile.Log（
        Nortel.IS.IDMS.LogFile.MessageTypes.ERROR，
        没有权限类型选择
        ）;
    返回;
}
布尔l_Success = SE.UI.Utilities.GetPermissionList（
    REF l_Monitor，
    REF m_CPermissions_ListBox，
    （INT）this.ViewState [m_Account_Share_ID]，
    （m_PermFolders_DropDownList.Enabled）
        ？ m_PermFolders_DropDownList.SelectedItem.Value
        ：-1，
    （SE.Types.PermissionType）m_PermType_RadioButtonList.SelectedIndex，
    （SE.Types.PermissionResource）m_PermResource_RadioButtonList.SelectedIndex）;
 

解决方案

您确保性能试图要在l_Monitor实例访问一个不为空？

This is a segment of code from an app I've inherited, a user got a Yellow screen of death:

Object reference not set to an instance of an object

on the line:

bool l_Success ... 

Now I'm 95% sure the faulty argument is ref l_Monitor which is very weird considering the object is instantiated a few lines before. Anyone have a clue why it would happen? Note that I have seen the same issue pop up in other places in the code.

IDMS.Monitor l_Monitor = new IDMS.Monitor();
l_Monitor.LogFile.Product_ID = "SE_WEB_APP";

if (m_PermType_RadioButtonList.SelectedIndex == -1) {
    l_Monitor.LogFile.Log(
        Nortel.IS.IDMS.LogFile.MessageTypes.ERROR,
        "No permission type selected"
        );
    return;
}
bool l_Success = SE.UI.Utilities.GetPermissionList(
    ref l_Monitor,
    ref m_CPermissions_ListBox,
    (int)this.ViewState["m_Account_Share_ID"],
    (m_PermFolders_DropDownList.Enabled)
        ? m_PermFolders_DropDownList.SelectedItem.Value
        : "-1",
    (SE.Types.PermissionType)m_PermType_RadioButtonList.SelectedIndex,
    (SE.Types.PermissionResource)m_PermResource_RadioButtonList.SelectedIndex);

解决方案

You sure that one of the properties trying to be accessed on the l_Monitor instance isn't null?

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