WMI查询空属性

Question

在下面的WMI查询中，如果proptery为空，那么我的代码错误。当属性不存在时，如何让代码返回“”？例如queryObj [“帮助电话”]为空，所以我的代码出错了，但我希望它继续。

ManagementObjectSearcher searcherSoftware = new ManagementObjectSearcher("root\\CIMV2", "Select * from Win32_Product"); 

foreach (ManagementObject queryObj in searcherSoftware.Get()) 
{ 
    ItemsUnderControlObject TemporarySoftware = new ItemsUnderControlObject(); 
    TemporarySoftware.sType = "Software"; 
    TemporarySoftware.sAssignmentType = queryObj["AssignmentType"].ToString().Split(new[] { "Name=" }, StringSplitOptions.None).Last().Trim('"'); //http://stackoverflow.com/questions/22583873/get-names-from-string-values/22583919?noredirect=1#22583919 
    TemporarySoftware.sCaption = queryObj["Caption"].ToString().Split(new[] { "Name=" }, StringSplitOptions.None).Last().Trim('"'); 
    TemporarySoftware.sDescription = queryObj["Description"].ToString().Split(new[] { "Name=" }, StringSplitOptions.None).Last().Trim('"'); 
    TemporarySoftware.sHelpLink = queryObj["HelpLink"].ToString().Split(new[] { "Name=" }, StringSplitOptions.None).Last().Trim('"'); 
    TemporarySoftware.sHelpTelephone = queryObj["Help Telephone"].ToString().Split(new[] { "Name=" }, StringSplitOptions.None).Last().Trim('"'); 
} 

Answer 1

可以创建一个辅助方法：

private static string GetNameContents(ManagementObject queryObj, string propertyName) 
{ 
    object propertyValue = queryObj[propertyName]; 
    if (propertyValue == null) 
     return String.Empty; 
    string propertyString = propertyValue.ToString(); 
    return propertyString.Length == 0 
     ? String.Empty 
     : propertyString.Split(new[] { "Name=" }, StringSplitOptions.None).Last().Trim('"'); 
} 

并且如下使用它：

TemporarySoftware.sAssignmentType = GetNameContents(queryObj, "AssignmentType"); 
TemporarySoftware.sCaption = GetNameContents(queryObj, "Caption");