[英]MS Word Automation in C# - Unable to cast object of type 'System.String[*]' to type 'System.String[]'
I use this code to get a String array of headings used in a MS Word 2007 document (.docx):我使用此代码获取 MS Word 2007 文档 (.docx) 中使用的标题字符串数组:
dynamic arr = Document.GetCrossReferenceItems(WdReferenceType.wdRefTypeHeading);
Using the debugger, I see that arr
is dynamically assigned a String array with titles of all my headings in the document (about 40 entries).使用调试器,我看到
arr
被动态分配了一个字符串数组,其中包含我在文档中所有标题的标题(大约 40 个条目)。 So far so good.到目前为止,一切都很好。
Then, I want to access the strings, but no matter how I do it, I get the following exception:然后,我想访问字符串,但无论如何我都会得到以下异常:
InvalidCastException:
Unable to cast object of type 'System.String[*]' to type 'System.String[]'.
I have tried different ways of accessing the strings:我尝试了不同的访问字符串的方法:
By index:按索引:
String arr_elem = arr[1];
By casting to an IEnumerable:通过转换为 IEnumerable:
IEnumerable list = (IEnumerable)arr;
By using a simple foreach loop:通过使用一个简单的 foreach 循环:
foreach (String str in arr)
{
Console.WriteLine(str);
}
However, no matter what I try, I always end up with the same exception as shown above.但是,无论我尝试什么,我总是会遇到与上图相同的异常。
Can anyone explain what I am missing here / what I am doing wrong?谁能解释我在这里缺少什么/我做错了什么? And especially
String[*]
- what does it mean?尤其是
String[*]
- 这是什么意思?
string[]
is a vector - a 1-d, 0-based array. string[]
是一个向量 - 一个从 0 开始的一维数组。 string[*]
, however, is a regular array that just happens to have one dimension .然而,
string[*]
是一个恰好只有一维的常规数组。 Basically, you are going to have to handle it as Array
, and either copy the data out, or use the Array
API rather than the string[]
API.基本上,您必须将其作为
Array
处理,然后将数据复制出来,或者使用Array
API 而不是string[]
API。
This is the same as the difference between typeof(string).MakeArrayType()
(the vector) and typeof(string).MakeArrayType(1)
(a 1-d non-vector).这与
typeof(string).MakeArrayType()
(向量)和typeof(string).MakeArrayType(1)
(一维非向量)之间的区别相同。
try尝试
object arr_r = Document.GetCrossReferenceItems(WdReferenceType.wdRefTypeHeading);
Array arr = ((Array) (arr_r));
string myHeading = (string) arr.GetValue(1);
The problem is that you're using dynamic
in a situation where it apparently wasn't intended.问题是您在显然不是故意的情况下使用
dynamic
。 When the dynamic runtime sees a 1D array, it assumes a vector, and tries to index into it or enumerate it as if it were a vector.当动态运行时看到一个一维数组时,它假定一个向量,并尝试对其进行索引或枚举它,就好像它是一个向量一样。 This is one of those rare cases where you have a 1D array that is not a vector, so you have to handle it as an
Array
:这是您拥有不是向量的一维数组的罕见情况之一,因此您必须将其作为
Array
处理:
Array arr = (Array)(object)Document.
GetCrossReferenceItems(WdReferenceType.wdRefTypeHeading);
// works
String arr_elem = arr.GetValue(1);
// now works
IEnumerable list = (IEnumerable)arr;
// now works
foreach (String str in arr)
{
Console.WriteLine(str);
}
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