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Silverlight 4應用程序的問題。 在這個應用程序中，每個客戶端會話創建一個獨立的進程，它調用一個DLL。Silverlight-DLL通信問題
與DLL的通信建立在以下調用堆棧中（對於兩個函數：一個工作，另一個 - 不）。
有2個函數的DLL（都工作得不錯）：
extern "C" BOOL __stdcall DocRunExternPageDividions(const char *docId, int num_form, int PageNum, int *Vcols, int **Vvalues, int *Hcols, int **Hvalues)
{
LOG_START_FUNCTION
BOOL res = 1;
__try {
res = DocRunExternPageDividions1(docId, num_form, PageNum, Vcols, Vvalues, Hcols, Hvalues);
}
__except(ExFilter(GetExceptionInformation()))
{
AfxThrowUserException();
}
LOG_STOP_FUNCTION
return res;
}
extern "C" BOOL __stdcall DocRunExternPageBreakRects(const char *docId, int num_form, int PageNum)
{
LOG_START_FUNCTION
BOOL res = 1;
__try {
res = DocRunExternPageBreakRects1(docId, num_form, PageNum);
}
__except(ExFilter(GetExceptionInformation()))
{
AfxThrowUserException();
}
LOG_STOP_FUNCTION
return res;
}
要調用這個函數服務器有兩個代表：
private delegate void DocRunExternPageBreakRectsDelegate(string docId, int DocNum, int PageNum);
private delegate void DocRunExternPageDividionsDelegate(
string docId, int DocNum, int PageNum, out int Vcols, out IntPtr VoutArray, out int Hcols,
out IntPtr HoutArray);
...兩個委託實例和對應功能：
private DocRunExternPageBreakRectsDelegate DocRunExternPageBreakRectsD;
DocRunExternPageBreakRectsD =
Marshal.GetDelegateForFunctionPointer(ptrDocRunExternPageBreakRects,
typeof (DocRunExternPageBreakRectsDelegate)) as
DocRunExternPageBreakRectsDelegate;
private DocRunExternPageDividionsDelegate DocRunExternPageDividionsD;
DocRunExternPageDividionsD =
Marshal.GetDelegateForFunctionPointer(ptrDocRunExternPageDividionsD,
typeof (DocRunExternPageDividionsDelegate)) as
DocRunExternPageDividionsDelegate;
public void DocRunExternPageDividions(string docId, int DocNum, int PageNum, out int[] vert, out int[] horz) {
IntPtr VoutArray, HoutArray;
int vcols, hcols;
DocRunExternPageDividionsD(docId, DocNum, PageNum, out vcols, out VoutArray, out hcols, out HoutArray);
marshal(VoutArray, out vert, vcols);
marshal(HoutArray, out horz, hcols);
}
public void DocRunExternPageBreakRects(string docId, int DocNum, int PageNum) {
DocRunExternPageBreakRectsD(docId, DocNum, PageNum);
}
在這裏調用這些函數（服務器代碼）：
public bool PageBreakRects(string docId, int DocNum, int PageNum, out int[] vert, out int[] horz) {
bool result;
vert = null;
horz = null;
Program.WriteUserMessage("Called PageBreakRects(" + docId + ", " + DocNum + ", " + PageNum + ")");
try {
DocRunExternPageBreakRects(docId, DocNum, PageNum);
DocRunExternPageDividions(docId, 0, PageNum, out vert, out horz);
result = true;
} catch (Exception ex) {}
return result;
}
public bool GetPageDividions(string docID, int Id, int pageNumber, out int[] vert, out int[] horz) {
bool result = false;
vert = null;
horz = null;
try {
DocRunExternPageDividions(docID, Id, pageNumber, out vert, out horz);
result = true;
} catch (Exception) {}
return result;
}
他們每個人 - 在這裏稱爲：
public DocDividionsResult PageBreakRects(string docID, int DocNum, int pageNumber) {
var result = new DocDividionsResult();
int[] vert;
int[] horz;
result.Data = new List<object> { Program.DllWrapper.PageBreakRects(docID, DocNum, pageNumber, out vert, out horz) };
result.Vert = vert;
result.Horz = horz;
return result;
}
public DocDividionsResult GetPageDividions(string docID, int formId, int pageNumber) {
var result = new DocDividionsResult();
int[] vert;
int[] horz;
result.Data = new List<object>
{Program.DllWrapper.GetPageDividions(docID, formId, pageNumber, out vert, out horz)};
result.Vert = vert;
result.Horz = horz;
return result;
}
然後 - 拉姆達表達式中：
public bool GetPageDividions(string docID, int formId, int pageNumber, out int[] vert, out int[] horz) {
bool result = false;
int []localVert = null;
int []localHorz = null;
if (_wp != null) {
if (Service<IWPCommunication>.Use(TestService =>
{
TestService.Test(UserId);
},
WPService =>
{
DocDividionsResult br = WPService.GetPageDividions(docID, formId, pageNumber);
if (br != null && br.Data != null && br.Data.Length == 1)
{
result = (bool)br.Data[0];
localVert = br.Vert;
localHorz = br.Horz;
}
}, Id, FS) == 0)
{
...
result = false;
}
}
vert = localVert;
horz = localHorz;
return result;
}
public bool PageBreakRects(string docId, int DocNum, int PageNum) {
bool result = false;
if (_wp != null)
{
if (Service<IWPCommunication>.Use(TestService =>
{
TestService.Test(UserId);
},
WPService =>
{
DocDividionsResult br = WPService.PageBreakRects(docId, DocNum, PageNum);
if (br != null && br.Data != null && br.Data.Length == 1) {
result = (bool)br.Data[0];
}
}, Id, FS) == 0)
{
...
result = false;
}
}
return result;
}
「使用」 功能（以上使用）：
public static int Use(UseServiceDelegate<T> codeTest, UseServiceDelegate<T> codeBlock, string SessionId, FileStream fs, bool throwException) {
IClientChannel texy = (IClientChannel)_testFactory.CreateChannel(new EndpointAddress("net.pipe://localhost/X2WPServiceUID" + SessionId));
IClientChannel proxy = (IClientChannel)_channelFactory.CreateChannel(new EndpointAddress("net.pipe://localhost/X2WPServiceUID" + SessionId));
int returnCode = 0;
try {
if (codeTest != null) {
codeTest((T)texy);
texy.Close();
}
returnCode = 1;
if (codeBlock != null) {
codeBlock((T)proxy);
proxy.Close();
}
returnCode = 2;
} catch(Exception e) {
if (returnCode == 1 && throwException)
throw e;
} finally {
if (returnCode == 0 && codeTest != null)
texy.Abort();
else if (returnCode == 1 && codeBlock != null)
proxy.Abort();
}
return returnCode;
}
客戶端通信被省略，因爲在第e服務器端。 GetPageDividions函數工作正常，bug PageBreakRects - 不是：行 DocDividionsResult br = WPService.PageBreakRects（docId，DocNum，PageNum）; 引發以下例外：
"The message with Action 'http://tempuri.org/IWPCommunication/PageBreakRects'
cannot be processed at the receiver, due to a ContractFilter mismatch at the EndpointDispatcher.
This may be because of either a contract mismatch (mismatched Actions between sender and receiver)
or a binding/security mismatch between the sender and the receiver.
Check that sender and receiver have the same contract and the same binding
(including security requirements, e.g. Message, Transport, None)."
更糟糕的是提的是，如果在功能PageBreakRects取代： DocDividionsResult BR = WPService.PageBreakRects（的docId，DocNum，頁次）; DocDividionsResult br = WPService.GetPageDividions（docID，formId，pageNumber）; 與 DocDividionsResult br = WPService.GetPageDividions（docID，formId，pageNumber）; 則不會引發異常。