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I would like to have a method that does something like the following,
public static object foo(object A, Type T) {
return (T)A;
}I don't explicitly know the type T anywhere in my code... it is found at runtime, so I CAN'T do the following (unless there is some way to send TObject.GetType() as T):
public static T foo<T>(object A) {
return (T)A;
}Oh, and object A cannot implement the IConvertable Interface (or any interface, for that matter, since I have NO control over the class), so I am unable to use the System.Convert.ChangeType method as well. I DO however know that either
1: type T defines an explicit cast operator from AType->T, OR
2: type AType defines an explicit cast operator from AType->T
but I can't figure out how to call that cast with the information I have. Does anyone know a way that I can accomplish this? Thanks,
Sounds like somebody's got a case of the Mondays
-Jeff
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Have you tried the "ChangeType" method of the "Convert" class?
It seems to be exactly your foo 
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"Convert.ChangeType" seems to be exactly your foo
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Yes, but to call that method the object must implement IConvertible (or at least, that's the exception I got at runtime when I tried it). The answer I used was given in the next post, but thanks for taking the time to help!
Sounds like somebody's got a case of the Mondays
-Jeff
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Hi
Basically an Operator is a static method, that you can call via reflection if you know the name of it.
let's say you have a class A and a class B
they look like this:
public class A
{
public static implicit operator B(A SourceObject)
{
return new B();
}
}
public class B
{
}
then the compiler compiles the operator as
public static B op_implicit(A SourceObject);
so, all you have to do, is to use reflection to find the static method that's called
op_implicit, takes an object of A as parameter and returns an object of B
hope this helps
greets
m@u
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private static readonly string[] s_CastOps = new string[] { "op_Explicit", "op_Implicit" };
public static T Convert<T, U>(U other) where T : new() {
T rval = new T();
foreach (PropertyInfo tPropInfo in typeof(T).GetProperties()) {
if (tPropInfo.GetCustomAttributes(typeof(System.Xml.Serialization.XmlIgnoreAttribute), true).Length > 0)
continue;
PropertyInfo uPropInfo = typeof(U).GetProperty(tPropInfo.Name);
if (uPropInfo != null && tPropInfo.CanWrite && uPropInfo.CanRead
&& uPropInfo.GetIndexParameters().Length == 0
&& tPropInfo.GetIndexParameters().Length == 0) {
Type tPropType = tPropInfo.PropertyType;
Type uPropType = uPropInfo.PropertyType;
if (tPropType.Equals(uPropType)) {
tPropInfo.SetValue(rval, uPropInfo.GetValue(other, null), null);
continue;
}
Type[] uPropTypeArray = new Type[] { uPropType };
object[] uValue = new object[] { uPropInfo.GetValue(other, null) };
ConstructorInfo tConstruct = tPropType.GetConstructor(uPropTypeArray);
if (tConstruct != null) {
tPropInfo.SetValue(rval, tConstruct.Invoke(uValue), null);
continue;
}
foreach (Type propType in new Type[] { tPropType, uPropType }) {
foreach (string castOp in s_CastOps) {
MethodInfo ConvertUtoT = propType.GetMethod(castOp, uPropTypeArray);
if (ConvertUtoT != null && tPropType.Equals(ConvertUtoT.ReturnType)) {
tPropInfo.SetValue(rval, ConvertUtoT.Invoke(null, uValue), null);
goto _endConvert;
}
}
}
_endConvert:
continue;
}
}
return rval;
}Basically, I go through the list of properties on both types. If both have a property with the same name, I try to copy the value from one to the other. If they are the same type, I simply set one to the other. Otherwise, I check if the result type has a constructor that takes the source type as a parameter. If so, I call the constructor. If not, then I look for a typecast definition between the two types (either explicit or implicit). If found, I cast the value of the source property to the type of the target property. This works great to copy objects with the same (or similar) properties into different types. Thanks for the help!
Sounds like somebody's got a case of the Mondays
-Jeff
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Hi,
I need to determine user role, especially if user is administrator. I know one way, but that way doesn't provide the information I need:
WindowsPrincipal principal = new WindowsPrincipal(WindowsIdentity.GetCurrent());
principal.IsInRole(WindowsBuiltInRole.Administrator);
the problem is that even if user is an administrator (on Vista) and the UAC is on , user still behaves like non-administrator user. Difference is when a UAC form is displayed. When an administrator is required to elevale a process to admin rights, he doesn't need to type in his (administrator) credentials. However a regular user does have to type in these credentianls (of course). So if an application is run under administrator but not elevated to administrator rights, the principal says that the Current User is not an administrator. I need to know if that user is an administrator not depending on current Thread/Appication granted rights.
thanx in advance... 
zilo
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I managed to do this by adding this class to my application:
using System;
using System.Collections.Generic;
using System.Text;
using System.Runtime.InteropServices;
using System.Security.Principal;
namespace Gauge
{
public static class mySecurity
{
#region Constants
const UInt32 TOKEN_QUERY = 8;
const int INT_SIZE = 4;
#endregion
#region Enumerations
private enum TOKEN_ELEVATION_TYPE
{
TokenElevationTypeDefault = 1,
TokenElevationTypeFull,
TokenElevationTypeLimited
}
public enum TOKEN_INFO_CLASS
{
TokenUser = 1,
TokenGroups,
TokenPrivileges,
TokenOwner,
TokenPrimaryGroup,
TokenDefaultDacl,
TokenSource,
TokenType,
TokenImpersonationLevel,
TokenStatistics,
TokenRestrictedSids,
TokenSessionId,
TokenGroupsAndPrivileges,
TokenSessionReference,
TokenSandBoxInert,
TokenAuditPolicy,
TokenOrigin,
TokenElevationType,
TokenLinkedToken,
TokenElevation,
TokenHasRestrictions,
TokenAccessInformation,
TokenVirtualizationAllowed,
TokenVirtualizationEnabled,
TokenIntegrityLevel,
TokenUIAccess,
TokenMandatoryPolicy,
TokenLogonSid,
MaxTokenInfoClass
// MaxTokenInfoClass should always be the last enum
}
#endregion
#region WIN API FUNCTIONS
[DllImport("kernel32.dll")]
public static extern IntPtr GetCurrentProcess();
[DllImport("advapi32.dll", SetLastError=true)]
public static extern Boolean OpenProcessToken(IntPtr ProcessHandle, UInt32 DesiredAccess, out IntPtr TokenHandle);
[DllImport("advapi32.dll", SetLastError=true)]
public static extern Boolean GetTokenInformation(IntPtr TokenHandle, TOKEN_INFO_CLASS TokenInformationClass,
IntPtr TokenInformation, int TokenInformationLength, out uint ReturnLength);
#endregion
#region Public Methods
///
/// Returns True when the current user is a member of the
/// Administrators group and is also running the process
/// elevated as an Administrator, otherwise returns false.
///
/// <returns>
/// <c>true if user is running the process elevated as an Administrator; otherwise, <c>false.
///
public static Boolean IsRunningAsAdmin(WindowsPrincipal pWindowsPrincipal)
{
return pWindowsPrincipal.IsInRole(WindowsBuiltInRole.Administrator);
}
///
/// Checks whether the user can elevate to Administrator rights.
///
/// <returns><c>true if user can elevate to Administrator rights; <c>false otherwise.
public static Boolean CanElevateToAdmin(WindowsPrincipal pWindowsPrincipal)
{
Boolean returnVal = false;
// Determine if the current user is already running with Administrator rights.
Boolean isAdmin = IsRunningAsAdmin(pWindowsPrincipal);
// Return True if the user is an Administrator (user must have Administration rights).
if (isAdmin)
return true;
OperatingSystem os = Environment.OSVersion;
Version vs = os.Version;
// If Vista or Higher, check for split token.
if (vs.Major > 5)
{
try
{
IntPtr myToken;
TOKEN_ELEVATION_TYPE elevationType;
uint dwSize;
IntPtr pElevationType = Marshal.AllocHGlobal(INT_SIZE);
// Get a token reference for the user running this process.
OpenProcessToken(GetCurrentProcess(), TOKEN_QUERY, out myToken);
// Get the elevation information for this token.
GetTokenInformation(myToken, TOKEN_INFO_CLASS.TokenElevationType, pElevationType,
INT_SIZE, out dwSize);
// Cast the result to ENUM_TYPE.
elevationType = (TOKEN_ELEVATION_TYPE)(Marshal.ReadInt32(pElevationType));
// Free allocated unmanaged memory.
Marshal.FreeHGlobal(pElevationType);
// Determine result of the elevation check.
// ==============================================
// TokenElevationTypeFull - User has a split token,
// and the process is running elevated
// TokenElevationTypeDefault - User is not using a split token
// ==============================================
returnVal = (elevationType == TOKEN_ELEVATION_TYPE.TokenElevationTypeLimited);
returnVal = returnVal || (elevationType == TOKEN_ELEVATION_TYPE.TokenElevationTypeFull);
}
catch
{
returnVal = false;
}
}
else
{
// Prior to Vista, only check needed is if user is in Administrators group.
returnVal = isAdmin;
}
return returnVal;
}
///
/// Checks if user is running as a standared user, but can elevate to Administrator rights.
///
/// <returns><c>true if user can elevate with their own credentials; <c>false otherwise.
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Hi everybody,
how can i use TAPI 2 into C#?
I made my project with TAPI 3, but the 3rd Version is buggy, the DISCONNECTED Event doesn't fire
each time if the call is over.
So i like to step to Version 2 of TAPI
Big thanks for help
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Hi
i have the following code which insetrs a value into the database, however it says the value is not in the correct format.
any help?
thanks
Session["Qty_New"] = tb_Qty_New.Text.;
cmd.Parameters.Add(new SqlParameter("@qty_new", SqlDbType.Int));
cmd.Parameters["@qty_new"].Value = Convert.ToInt32(Session["Qty_New"]);
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Jamie1985 wrote: wever it says the value is not in the correct format.
any help?
Yes, obviously ensure Session["Qty_New"] has data, and that that data can be converted to an int before converting it.
Check out int.TryParse rather than Convert.ToInt32
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Two things - you don't actually need to convert the session to an int to assign it to the parameter. Also, you should check to see if Session["Qty_New"] is null or an empty string before using it.
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Hi
are you sure i dont need to convert to int, i took it out and left it like this
string Qty_New
Qty_New = tb_Qty_New.Text;
cmd.Parameters.Add(new SqlParameter("@qty_new", SqlDbType.Int));
cmd.Parameters["@qty_new"].Value = Qty_New;
however this doesnt work
there is a value in Qty_New
cheers
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Any leading/trailing space character in that?
Vasudevan Deepak Kumar
Personal Homepage
Tech Gossips
A pessimist sees only the dark side of the clouds, and mopes; a philosopher sees both sides, and shrugs; an optimist doesn't see the clouds at all - he's walking on them. --Leonard Louis Levinson
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no just a one digit number in the text box value
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fixed it
the textbox value was set on page_load instead of the onlclick
thanks
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Hi all,
I want to sending an XML string using webservice installed at server to the client using IP(internet IP) and then further want to save it in the from of XML file.
can anybody tell me how to do it???
Thanks in advance.
Ankur
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can we hide focus from grid cell
amit
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how do i redirect to anther page when i only know the path of the libery?
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 Your post doesn't make much sense. Redirect what?
wrote: when i only know the path of the libery?
Is not clear at all.
"Real programmers just throw a bunch of 1s and 0s at the computer to see what sticks" - Pete O'Hanlon
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how to deactivate grid cell if it is active.
amit
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I want to know what is happening in these lines of code:
a)
public class cAppBarDisplay:AppBar
{
cMessageProcessing CMS;
public cAppBarDisplay(cMessageProcessing cMP)
{
CMS = cMP;
}
}
->cMessageProcessing CMS;
By this mean are we creating a refrence?
->and what the constructer is actually doing?
CMS & cMP both are refrence of same class
Thanks in advance,
plz describe in a bit detail.
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humdumof wrote: ->cMessageProcessing CMS;
By this mean are we creating a refrence?
You created a field called CMS, which you can set to reference an instance of cMessageProcessing. This happens when you do CMS = cMP for example.
humdumof wrote: CMS = cMP;//exactly what is happening here
You assign the parameter cMP to the field CMS. They now hold the same reference to an instance of the cMessageProcessing class (not a reference to the class itself).
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AlwiNus wrote: You assign the parameter cMP to the field CMS. They now hold the same reference to an instance of the cMessageProcessing class (not a reference to the class itself).
Not a refrence to the class itself?
By this what u mean?
also CMS=cMP;
Does it mean we can access all the methods of cMessageProcessing thru CMS?
& what is use of doing all this in constructor?
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