C# Discussion Boards - CodeProject

Re: Change a version of pdf

Dave Kreskowiak9-Mar-09 3:29

Dave Kreskowiak

9-Mar-09 3:29

You're going to have to explain what you mean by "change the version of PDF"...

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Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007, 2008

Re: Change a version of pdf

abbd9-Mar-09 3:34

abbd

9-Mar-09 3:34

When i generate a pdf with i can't set it on version 1.7, so it is on 1.4, i will cherche how i can change the version of my pdf file to 1.7, thank you verry mutch.

Re: Change a version of pdf

Dave Kreskowiak9-Mar-09 4:43

Dave Kreskowiak

9-Mar-09 4:43

That made no sense what-so-ever...

I think you're going to have to consult the documentation on the PDF library you're using. I can't make heads or tails of your description.

A guide to posting questions on CodeProject[^]

Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007, 2008

Re: Change a version of pdf

DaveyM699-Mar-09 5:13

DaveyM69

9-Mar-09 5:13

I think he means the version number that shows up when you right click, select Properties and then the PDF tab.

Dave
BTW, in software, hope and pray is not a viable strategy. (Luc Pattyn)
Visual Basic is not used by normal people so we're not covering it here. (Uncyclopedia)

Re: Change a version of pdf

Dave Kreskowiak9-Mar-09 7:53

Dave Kreskowiak

9-Mar-09 7:53

DaveyM69 wrote:
I think he means the version number that shows up when you right click...

Rule #1 in troubleshooting: You either "know" or you don't. "Thinking" is not allowed.

A guide to posting questions on CodeProject[^]

Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007, 2008

Re: Change a version of pdf

DaveyM699-Mar-09 10:17

DaveyM69

9-Mar-09 10:17

Note to self... Stop thinking.

There, that's that done Laugh | :laugh:

Dave
BTW, in software, hope and pray is not a viable strategy. (Luc Pattyn)
Visual Basic is not used by normal people so we're not covering it here. (Uncyclopedia)

Amin.mosbat9-Mar-09 0:53

Amin.mosbat

9-Mar-09 0:53

hi i want to khnow how i can added a image in database(sql)?

whit forms in c#???

Re: c#

dan!sh 9-Mar-09 0:59

dan!sh

9-Mar-09 0:59

Like this[^]

Happy Holi[^]
जय हिंद

Re: c#

Paw Jershauge9-Mar-09 1:39

Paw Jershauge

9-Mar-09 1:39

Please use the search function before submitting your question here, thanks...

look here http://www.codeproject.com/KB/web-image/EasyThumbs.aspx[^]

With great code, comes great complexity, so keep it simple stupid... $Shucks | :-\$ $Shucks | :-\$

Creating you own Nullable<t></t>

Paw Jershauge9-Mar-09 0:25

Paw Jershauge

9-Mar-09 0:25

Im not sure if this can be done.

But i want to create my on Nullable<t> struct.
my problem is that i cant assign null to my struct as it is an non-nullable type, how can i overcome this ?

Heres my attemt:

[Serializable, StructLayout(LayoutKind.Sequential)]
public struct Null<T> where T : struct
{
    private bool hasValue;
    private bool allowNull;
    internal T value;
    public Null(T value)
    {
        this.value = value;
        this.hasValue = true;
        this.allowNull = true;
    }

    public bool HasValue
    {
        get
        {
            return this.hasValue;
        }
    }
    public bool AllowNull
    {
        get
        {
            return this.allowNull;
        }
    }
    public T Value
    {
        get
        {
            if (!this.HasValue)
            {
                throw new InvalidOperationException("No Value!");
            }
            return this.value;
        }
    }
    public T GetValueOrDefault()
    {
        return this.value;
    }

    public T GetValueOrDefault(T defaultValue)
    {
        if (!this.HasValue)
        {
            return defaultValue;
        }
        return this.value;
    }

    public override bool Equals(object other)
    {
        if (!this.HasValue)
        {
            return (other == null);
        }
        if (other == null)
        {
            return false;
        }
        return this.value.Equals(other);
    }

    public override int GetHashCode()
    {
        if (!this.HasValue)
        {
            return 0;
        }
        return this.value.GetHashCode();
    }

    public override string ToString()
    {
        if (!this.HasValue)
        {
            return "";
        }
        return this.value.ToString();
    }

    public static implicit operator Null<T>(T value)
    {
        return new Null<T>(value);
    }

    public static explicit operator T(Null<T> value)
    {
        return value.Value;
    }
}

This is all fine but when i then try to use it i get an non-nullable type exception:

Example:
private Null<int> index = null;

the null; assignment returns the following error:
Error 4 Cannot convert null to 'Null<int>' because it is a non-nullable value type

Can this be done,if so HELP please, or am i on an wrong track here ?

With great code, comes great complexity, so keep it simple stupid... $Shucks | :-\$ $Shucks | :-\$

Re: Creating you own Nullable

ABitSmart9-Mar-09 0:39

ABitSmart

9-Mar-09 0:39

You can have a Nullable structure.

struct Dummy{
    public string dummyvalue;
}

Dummy? dummyStrct = null; //This is possible

Re: Creating you own Nullable

Paw Jershauge9-Mar-09 1:19

Paw Jershauge

9-Mar-09 1:19

Well this is exactly what im trying to avoid. i know that ? equals the Nullable<t> but what i want to do here is, create another Nullable<t> structure, where i can put my own members into. please look at my samlpe again, and see what im trying to accomplish. Wink | ;)

Thanks for you awnser. Wink | ;)

With great code, comes great complexity, so keep it simple stupid... $Shucks | :-\$ $Shucks | :-\$

Re: Creating you own Nullable

ABitSmart9-Mar-09 1:29

ABitSmart

9-Mar-09 1:29

You have been very polite Rose | [Rose]

Re: Creating you own Nullable [modified]

harold aptroot9-Mar-09 0:51

harold aptroot

9-Mar-09 0:51

Maybe if you make an implicit cast operator from object to Null<T>? The object could be null, obviously, so if you tried to assign null to it it should think the null is an object and call your implicit cast operator.

Last modified: 29mins after originally posted --

Re: Creating you own Nullable

Paw Jershauge9-Mar-09 1:26

Paw Jershauge

9-Mar-09 1:26

Hmm maybe your on to something here... So far i accomplished the code by making the structure as an class instead, but in reality, i want it to be an struct.

I tried another approach by casting the implicit operator as an null or trypeof(null), but we all know thats gonna happen. Wink | ;)

so im thinking: lets just convert this struct into an class which can be null. Wink | ;)

I hate the fact, that Microsoft can acoomplish this, by making the Nullable<t> structure, but we as developers cannot... grrrrrrrrr D'Oh! | :doh:

With great code, comes great complexity, so keep it simple stupid... $Shucks | :-\$ $Shucks | :-\$

Re: Creating you own Nullable

harold aptroot9-Mar-09 1:32

harold aptroot

9-Mar-09 1:32

They cheat by making the compiler support it, which we can't do Frown | :(

Anyhow did an implicit cast from an object work?

Re: Creating you own Nullable

Paw Jershauge9-Mar-09 1:36

Paw Jershauge

9-Mar-09 1:36

Yeah your right... they have the advantage here Wink | ;)

Yes the casting on an object works bacause the object in its nature can be null.

So heres the code which works just fine (BUT ITS AN CLASS... grrrrrrrr, i wanted an struct. Wink | ;)

)

[Serializable, StructLayout(LayoutKind.Sequential)]
public class Null<T> where T : struct
{
    private bool hasValue;
    private bool allowNull;
    internal T value;
    public Null(T value)
    {
        this.value = value;
        this.hasValue = true;
        this.allowNull = true;
    }
    public Null(T value,bool allownull)
    {
        this.value = value;
        this.hasValue = true;
        this.allowNull = allownull;
    }
    public Null(bool allownull)
    {
        this.hasValue = false;
        this.allowNull = allownull;
    }
    public Null()
    {
        this.hasValue = false;
        this.allowNull = false;
    }

    public bool HasValue
    {
        get
        {
            return this.hasValue;
        }
    }
    public bool AllowNull
    {
        get
        {
            return this.allowNull;
        }
    }
    public T Value
    {
        get
        {
            if (!this.HasValue)
            {
                throw new InvalidOperationException("No Value!");
            }
            return this.value;
        }
    }
    public T GetValueOrDefault()
    {
        return this.value;
    }

    public T GetValueOrDefault(T defaultValue)
    {
        if (!this.HasValue)
        {
            return defaultValue;
        }
        return this.value;
    }

    public override bool Equals(object other)
    {
        if (!this.HasValue)
        {
            return (other == null);
        }
        if (other == null)
        {
            return false;
        }
        return this.value.Equals(other);
    }

    public override int GetHashCode()
    {
        if (!this.HasValue)
        {
            return 0;
        }
        return this.value.GetHashCode();
    }

    public override string ToString()
    {
        if (!this.HasValue)
        {
            return "";
        }
        return this.value.ToString();
    }

    public static implicit operator Null<T>(T value)
    {
        return new Null<T>(value);
    }

    public static explicit operator T(Null<T> value)
    {
        return value.Value;
    }
}

With great code, comes great complexity, so keep it simple stupid... $Shucks | :-\$ $Shucks | :-\$

Re: Creating you own Nullable

harold aptroot9-Mar-09 1:41

harold aptroot

9-Mar-09 1:41

Ok well the idea was that make a

public static implicit operator Null<T>(object value)
{
    if (value is T)
        return new Null<T>(value);
    else if (value == null)
        return new Null<T>(null, true);
    else
        throw new Exception("this is bad, but find a better exception");
}

And then Null<t> can be a struct, I think. Try first..

Re: Creating you own Nullable

Paw Jershauge9-Mar-09 1:50

Paw Jershauge

9-Mar-09 1:50

Ahhh sorry didnt see that one, no this is not allowed, as it tries to convert from a base class which is not allowed.

Following error returned:

Null<T>.implicit operator Null<T>(object)': user-defined conversions to or from a base class are not allowed

With great code, comes great complexity, so keep it simple stupid... $Shucks | :-\$ $Shucks | :-\$

Re: Creating you own Nullable

harold aptroot9-Mar-09 2:14

harold aptroot

9-Mar-09 2:14

Ok, didn't think of that, than use something else that is not a base type - say string, or some little holder class that does nothing except have the ability to be null.
Does it even say that when Null<T> is a struct?

Re: Creating you own Nullable

Paw Jershauge9-Mar-09 2:55

Paw Jershauge

9-Mar-09 2:55

Yes it does tell me that the Null is as struct.
And i think i found a work around.

oddly enought this seems to work:

public static implicit operator Null<T>(T? value)
{
    return new Null<T>(value.Value);
}

public static explicit operator T?(Null<T> value)
{
    return value.Value;
}

but at what cost this works, i havnt seen yet.

I will be trying with it for now. or go back to my struct as an class. Wink | ;)

Thanks alot for tackling this usue with me, Harold.

With great code, comes great complexity, so keep it simple stupid... $Shucks | :-\$ $Shucks | :-\$

Re: Creating you own Nullable

harold aptroot9-Mar-09 2:59

harold aptroot

9-Mar-09 2:59

Ok good, you're welcome Smile | :)

Re: Creating you own Nullable

Paw Jershauge9-Mar-09 3:38

Paw Jershauge

9-Mar-09 3:38

Hmm Harold, Blush | :O

normaly this would be the time, where i give beer. D'Oh! | :doh:

Mannnnnnn i somehow got so tangled up in this, that i somwehow swaped the
explicit and the implicit... man ohhh man ohhh man.... sooooooo sorry

this works just fint in the struct:

public static explicit operator Null<T>(T value)
{
    return new Null<T>(value);
}

public static implicit operator T(Null<T> value)
{
    return value.Value;
}

as where i before used (which of cause did not work.):

public static implicit operator Null<T>(T value)
{
    return new Null<T>(value);
}

public static explicit operator T(Null<T> value)
{
    return value.Value;
}

With great code, comes great complexity, so keep it simple stupid... $Shucks | :-\$ $Shucks | :-\$

Re: Creating you own Nullable

DaveyM699-Mar-09 2:22

DaveyM69

9-Mar-09 2:22

Can't you use
private Null<int?> index = null;
or
private Null<int>? index = null;

Dave
BTW, in software, hope and pray is not a viable strategy. (Luc Pattyn)
Visual Basic is not used by normal people so we're not covering it here. (Uncyclopedia)

Re: Creating you own Nullable

Paw Jershauge9-Mar-09 2:57

Paw Jershauge

9-Mar-09 2:57

hey DaveyM69

This is not what im trying to accomplish. I want my own Nullable (?) struct and not use the original one. ;o) but thanks for your suggestion. Wink | ;)

With great code, comes great complexity, so keep it simple stupid... $Shucks | :-\$ $Shucks | :-\$

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