带引号和不带引号的 WM_COPYDATA 会产生不同的结果
使用 WM_COPYDATA 通过 Delphi XE 将命令行参数传递到另一个应用程序实例，如下所示：
function DAppInstance.SendParamsToPrevInstance(AWindowHandle: THandle): Boolean;
var
copyData: TCopyDataStruct;
cmdParams : string;
i : integer;
begin
cmdParams := '';
for i := 1 to ParamCount do
cmdParams := cmdParams + ParamStr(i); //#1
//cmdParams := cmdParams + '"' + ParamStr(i) + '" '; //#2
//cmdParams := cmdParams + format('"%s" ', [ParamStr(i)]); //#3
//cmdParams := cmdParams + format('%s;', [ParamStr(i)]); //#4
copyData.lpData := pchar(cmdParams);
copyData.cbData := 1 + (bytelength(cmdParams));
copyData.dwData := WaterMark; //ID for APP
result := SendMessage(AWindowHandle,
WM_COPYDATA,
Application.Handle,
LPARAM(@copyData)) = 1;
end;
如果引用/附加字符串，则会产生不同的结果。
如果使用 #1 - 字符串是干净的，但如果不加引号则不可用，因为文件名可以有空格，并且 this:
C:\Users\MX4399\Research\delphi\instance\doc with spaces.doc
最后将被视为 3 个参数，同时使用 #2 引用字符串或附加任何内容 (# 3、#4) 原因
"C:\Users\MX4399\Research\delphi\instance\doc with spaces.doc"'#$FF00'궳獧
Using WM_COPYDATA to pass command line params to another app instance with Delphi XE as follows:
function DAppInstance.SendParamsToPrevInstance(AWindowHandle: THandle): Boolean;
var
copyData: TCopyDataStruct;
cmdParams : string;
i : integer;
begin
cmdParams := '';
for i := 1 to ParamCount do
cmdParams := cmdParams + ParamStr(i); //#1
//cmdParams := cmdParams + '"' + ParamStr(i) + '" '; //#2
//cmdParams := cmdParams + format('"%s" ', [ParamStr(i)]); //#3
//cmdParams := cmdParams + format('%s;', [ParamStr(i)]); //#4
copyData.lpData := pchar(cmdParams);
copyData.cbData := 1 + (bytelength(cmdParams));
copyData.dwData := WaterMark; //ID for APP
result := SendMessage(AWindowHandle,
WM_COPYDATA,
Application.Handle,
LPARAM(@copyData)) = 1;
end;
yields different results if the strings are quoted / appended to.
if #1 is used - the string comes in clean but is not usable if not quoted as filenames can have spaces and this:
C:\Users\MX4399\Research\delphi\instance\doc with spaces.doc
will be see as 3 paramaters in the end, while using #2 to quote the strings, or appending anything (#3, #4) causes
"C:\Users\MX4399\Research\delphi\instance\doc with spaces.doc"'#$FF00'궳獧
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评论（3）
我相信@TOndrej 已经发现了问题的主要原因。然而，我认为你还有第二个更微妙的错误。
我认为，接收
WM_COPYDATA消息的应用程序会将lpData视为以 null 结尾的字符串。如果数据格式错误，那么缓冲区就会溢出。我相信这正是您的示例中发生的情况，但事实证明它是良性的。WM_COPYDATA的编组仅复制cbData中指定的缓冲区大小。你必须确保你没有阅读超出它的内容。恶意应用程序可能会向您发送包含数据的WM_COPYDATA消息，迫使您执行此操作。相反，我建议您在阅读时使用cbData。因此，要发送您编写的字符串：
然后，当您收到它时，您会分配一个缓冲区并根据
cbData的值复制到该缓冲区。I believe that @TOndrej has spotted the main cause of the problem. However, I think you have a second more subtle bug.
Your app which receives the
WM_COPYDATAmessage is, I think, treatinglpDataas a null-terminated string. If the data is malformed then you will have a buffer overrun. I believe that is exactly what is happening in your examples but it just turns out to be benign. The marshalling ofWM_COPYDATAcopies just the size of buffer specified incbData. You must make sure you don't read beyond it. A malicious app could send you aWM_COPYDATAmessage with data to make you do just that. Instead I recommend you usecbDatawhen reading.So to send the string you write:
And then when you receive it you allocate a buffer and copy to that buffer based on the value of
cbData.我认为您的意思是
copyData.cbdata := 1 * SizeOf(Char) + ...而不仅仅是1 + ...。I think you meant
copyData.cbdata := 1 * SizeOf(Char) + ...instead of just1 + ....在一个单独但相关的注释中，您可以只使用
ParamStr()（它本身有许多已知的错误）来解析原始命令行并从中重建一个新字符串，而不是使用 < code>GetCommandLine() 来获取原始命令行并按原样发送。On a separate but related note, rather then using
ParamStr()(which itself has a number of known bugs) to parse the original command-line and rebuild a new string from it, you could just useGetCommandLine()to get the original command-line instead and send it as-is.