internal HSZ CreateStringHandle(string text)
{
if (text.Length > 255)
{
Trace.WriteLine(String.Format("A string cannot be wrapped to a DDE string because it's too long for that. It's {0} chars while the limit is 255. The original string is \"{1}\", was truncated down to the required length.", text.Length, text), "[DDE]");
text = text.Substring(0, 255);
}
byte[] ps = Encoding.ASCII.GetBytes(text);
byte[] psz = new byte[ps.Length + 1];
ps.CopyTo(psz, 0);
psz[psz.Length - 1] = 0;
HSZ handle = DdeCreateStringHandle(_instance, psz, Win32Declarations.CP_WINANSI); // TODO: winneutral
// Error checks
if (handle == IntPtr.Zero)
{
throw new DdeException("Cannot create a DDE handle of the string.", GetLastError());
}
DdeError dwErr = GetLastError();
if (dwErr != DdeError.DMLERR_NO_ERROR)
{
throw new DdeException("Cannot create a DDE handle of the string.", dwErr);
}
return(handle);
}
/// <summary>
/// Provides a human-readable string representation of a DDE raw error code.
/// </summary>
/// <param name="error">DDE error.</param>
/// <returns>Error string.</returns>
public static string ErrorToString(DdeError error)
{
// Return a string message, if available, or a numerical code otherwise
object message;
lock (_hashErrorMessages)
message = _hashErrorMessages[error];
return(message != null?message.ToString() : String.Format("An unknown DDE error {0} has occured.", (uint)error));
}
/// <summary>
/// Initializes the use of DDE.
/// </summary>
public Dde()
{
if (_instance != 0)
{
throw new InvalidOperationException("Must be uninitialized.");
}
CheckOwnerThread();
// Initialize as a client
_ddecallback = new PFNCALLBACK(DdeCallback);
DdeError dwError = DdeInitialize(ref _instance, _ddecallback, (uint)AfCmd.APPCMD_CLIENTONLY, 0u); // TODO: callback collected
if (dwError != DdeError.DMLERR_NO_ERROR)
{
throw new DdeException("Failed to initialize DDE.", dwError);
}
}
/// <summary>
/// Creates an exception that consists of a raw DDE error code.
/// </summary>
/// <param name="error">Raw error code.</param>
public DdeException(DdeError error)
: base(ErrorToString(error))
{
_error = error;
}
/// <summary>
/// Creates an exception that consists of a text message and a raw DDE error code.
/// </summary>
/// <param name="message">Text message.</param>
/// <param name="error">Raw error code.</param>
public DdeException(string message, DdeError error)
: base(message + " " + ErrorToString(error))
{
_error = error;
}
