Casting question

**Stefan Hoffmann** · Sep 24 '08, 02:45 PM

Re: Casting question

hi Dan,

Dan Tallent wrote:

private ArrayList DevControls;
DevControls = new ArrayList();
DevControls.Add (typeof(System. Windows.Forms.T extBox));
DevControls.Add (typeof(System. Windows.Forms.C omboBox));
Type oType = oControl.GetTyp e();
for (int cnt = 0; cnt<DevControls .Count; cnt++)
{
if (DevControls[cnt] == oType)
{
( (DevControls[cnt]) oControl).ReadO nly = true;

(DevControls[cnt]) doesn't contains a control.
Using

DevControls.Add (new ComboBox());

should work.

mfG
--stefan <--

**Alberto Poblacion** · Sep 24 '08, 02:55 PM

Re: Casting question

It's not exactly what you were asking, but you can achieve a similar result
by means of System.Reflecti on:

Type t = oControl.GetTyp e();
PropertyInfo pi = t.GetProperty(" ReadOnly");
if (pi!=null)
{
pi.SetValue(oCo ntrol, true, null);
}

"Dan Tallent" <spam@microsoft .comwrote in message
news:u0ZtgElHJH A.4084@TK2MSFTN GP04.phx.gbl...

>I have code here that checks the type of an object and then cast it so I
>can access its properties. In the simple example below I am accessing the
>ReadOnly property that is unique to textbox controls. This code works
>however I wanted to find out if its possible to write code using a
>collection or array.. see below
>
>
Type oType = oControl.GetTyp e();
if (oType == typeof(System.W indows.Forms.Te xtBox))
>
{
>
((System.Window s.Forms.TextBox )oControl).Read Only == true;
>
}
>
//=============== =============== =============== =
>
So the code below is kinda what I have in mind. Notice the line where
I am attempting to cast. I know this code
>
doesn't work, but I am wondering if there is a way to code such a routine.
>
//=============== =============== =============== =
>
private ArrayList DevControls;
>
DevControls = new ArrayList();
>
DevControls.Add (typeof(System. Windows.Forms.T extBox));
>
DevControls.Add (typeof(System. Windows.Forms.C omboBox));
>
Type oType = oControl.GetTyp e();
>
for (int cnt = 0; cnt<DevControls .Count; cnt++)
>
{
>
if (DevControls[cnt] == oType)
>
{
>
// This line below is the question... is there a way to
code this ?
>
( (DevControls[cnt]) oControl).ReadO nly = true;
>
}
>
}
>

**Dan Tallent** · Sep 24 '08, 03:05 PM

Re: Casting question

I thought about using reflection, the problem I am having there is the some
of the controls I'm working with have "sub-properites".

Example: The reach the actual property I would write code like this.
TextBox1.Proper ties.ReadOnly = true;

I'm not sure how to get to the sub-properties using reflection.

Thanks
Dan

"Alberto Poblacion" <earthling-quitaestoparaco ntestar@poblaci on.orgwrote
in message news:u%23iqkPlH JHA.1364@TK2MSF TNGP04.phx.gbl. ..

It's not exactly what you were asking, but you can achieve a similar
result by means of System.Reflecti on:
>
Type t = oControl.GetTyp e();
PropertyInfo pi = t.GetProperty(" ReadOnly");
if (pi!=null)
{
pi.SetValue(oCo ntrol, true, null);
}
>
>
>
"Dan Tallent" <spam@microsoft .comwrote in message
news:u0ZtgElHJH A.4084@TK2MSFTN GP04.phx.gbl...

>>I have code here that checks the type of an object and then cast it so I
>>can access its properties. In the simple example below I am accessing the
>>ReadOnly property that is unique to textbox controls. This code works
>>however I wanted to find out if its possible to write code using a
>>collection or array.. see below
>>
>>
>Type oType = oControl.GetTyp e();
>if (oType == typeof(System.W indows.Forms.Te xtBox))
>>
>{
>>
> ((System.Window s.Forms.TextBox )oControl).Read Only == true;
>>
>}
>>
>//=============== =============== =============== =
>>
>So the code below is kinda what I have in mind. Notice the line where
>I am attempting to cast. I know this code
>>
>doesn't work, but I am wondering if there is a way to code such a
>routine.
>>
>//=============== =============== =============== =
>>
>private ArrayList DevControls;
>>
>DevControls = new ArrayList();
>>
>DevControls.Ad d(typeof(System .Windows.Forms. TextBox));
>>
>DevControls.Ad d(typeof(System .Windows.Forms. ComboBox));
>>
>Type oType = oControl.GetTyp e();
>>
>for (int cnt = 0; cnt<DevControls .Count; cnt++)
>>
>{
>>
> if (DevControls[cnt] == oType)
>>
> {
>>
> // This line below is the question... is there a way to
>code this ?
>>
> ( (DevControls[cnt]) oControl).ReadO nly = true;
>>
> }
>>
>}
>>

>

**Dan Tallent** · Sep 24 '08, 03:05 PM

Re: Casting question

Hi Stefan,

This method doesn't work because the code won't compile. I believe the
problem is that the DevControls[cnt] is not a known type.
((DevControls[cnt])oControl).Read Only = true;

In traditional casting code like below uses a known type.
((System.Window s.Forms.TextBox )oControl).Read Only = true;

I am trying to find a way where I can loop throught each control on the form
and set its properties based on its Type.

Thx
Dan

"Stefan Hoffmann" <stefan.hoffman n@explido.dewro te in message
news:OlnsrNlHJH A.1088@TK2MSFTN GP02.phx.gbl...

hi Dan,
>
Dan Tallent wrote:

>private ArrayList DevControls;
>DevControls = new ArrayList();
>DevControls.Ad d(typeof(System .Windows.Forms. TextBox));
>DevControls.Ad d(typeof(System .Windows.Forms. ComboBox));
>Type oType = oControl.GetTyp e();
>for (int cnt = 0; cnt<DevControls .Count; cnt++)
>{
> if (DevControls[cnt] == oType)
> {
> ( (DevControls[cnt]) oControl).ReadO nly = true;

(DevControls[cnt]) doesn't contains a control.
Using
>
DevControls.Add (new ComboBox());
>
should work.
>
>
mfG
--stefan <--
>

**Alberto Poblacion** · Sep 24 '08, 03:35 PM

Re: Casting question

"Dan Tallent" <spam@microsoft .comwrote in message
news:%238sGlUlH JHA.4564@TK2MSF TNGP02.phx.gbl. ..

>I thought about using reflection, the problem I am having there is the some
>of the controls I'm working with have "sub-properites".
>
Example: The reach the actual property I would write code like this.
TextBox1.Proper ties.ReadOnly = true;
>
I'm not sure how to get to the sub-properties using reflection.

No problem. Just repeat the operation twice:

Type t1 = oControl.GetTyp e();
PropertyInfo pi1 = t1.GetProperty( "Properties ");
if (pi1!=null)
{
object prop = pi1.GetValue(oC ontrol, null);
Type t2 = prop.GetType();
PropertyInfo pi2 = t2.GetProperty( "ReadOnly") ;
if (p2i!=null)
{
pi.SetValue(pro p, true, null);
}
}

**Peter Duniho** · Sep 24 '08, 05:15 PM

Re: Casting question

On Wed, 24 Sep 2008 07:23:42 -0700, Dan Tallent <spam@microsoft .comwrote:

I have code here that checks the type of an object and then cast it so I
can
access its properties. In the simple example below I am accessing the
ReadOnly property that is unique to textbox controls. This code works
however I wanted to find out if its possible to write code using a
collection or array.. see below [...]

Since the ComboBox class doesn't have a ReadOnly property, I don't really
understand the code example you posted. Hopefully Alberto's comments
about reflection put you on the right track (absent a valid example, they
seem reasonably appropriate). But if you meant something else, you may
want to restate the example so that it makes more sense.

Pete

**Ignacio Machin ( .NET/ C# MVP )** · Sep 24 '08, 06:35 PM

Re: Casting question

On Sep 24, 10:23 am, "Dan Tallent" <s...@microsoft .comwrote:

I have code here that checks the type of an object and then cast it so I can
access its properties. In the simple example below I am accessing the
ReadOnly property that is unique to textbox controls. This code works
however I wanted to find out if its possible to write code using a
collection or array.. see below
>
Type oType = oControl.GetTyp e();
if (oType == typeof(System.W indows.Forms.Te xtBox))
>
{
>
((System.Window s.Forms.TextBox )oControl).Read Only == true;
>
}

A better approach is
TextBox tb = oControl as TextBox;
if ( tb!= null ){
}

you can use the same technique if the number of alternatives is nt too
long.
A more general solution would be using a dictionary:
Dictionary< Type, stringwhere the value indicate the name of the
property you want.
You could have:
< typeof(TextBox) , "readOnly"> ;
< typeof(DropDown ), "SelectedIndex" >;

Then you have a method that using reflection get the value based on
the dictionary:

object o = GetValue( instance, dcitionary[ typeof(oControl]);

**Ignacio Machin ( .NET/ C# MVP )** · Sep 24 '08, 06:45 PM

Re: Casting question

On Sep 24, 10:52 am, "Dan Tallent" <s...@microsoft .comwrote:

I thought about using reflection, the problem I am having there is the some
of the controls I'm working with have "sub-properites".
>
Example: The reach the actual property I would write code like this.
TextBox1.Proper ties.ReadOnly = true;
>
I'm not sure how to get to the sub-properties using reflection.
>
Thanks
Dan
>
"Alberto Poblacion" <earthling-quitaestoparaco ntes...@poblaci on.orgwrote
in messagenews:u%2 3iqkPlHJHA.1364 @TK2MSFTNGP04.p hx.gbl...
>

It's not exactly what you were asking, but you can achieve a similar
result by means of System.Reflecti on:

>

Type t = oControl.GetTyp e();
PropertyInfo pi = t.GetProperty(" ReadOnly");
if (pi!=null)
{
pi.SetValue(oCo ntrol, true, null);
}

>

"Dan Tallent" <s...@microsoft .comwrote in message
news:u0ZtgElHJH A.4084@TK2MSFTN GP04.phx.gbl...

>I have code here that checks the type of an object and then cast it so I
>can access its properties. In the simple example below I am accessing the
>ReadOnly property that is unique to textbox controls. This code works
>however I wanted to find out if its possible to write code using a
>collection or array.. see below

>

Type oType = oControl.GetTyp e();
if (oType == typeof(System.W indows.Forms.Te xtBox))

>

{

>

((System.Window s.Forms.TextBox )oControl).Read Only == true;

>

}

>

//=============== =============== =============== =

>

So the code below is kinda what I have in mind. Notice the line where
I am attempting to cast. I know this code

>

doesn't work, but I am wondering if there is a way to code such a
routine.

>

//=============== =============== =============== =

>

private ArrayList DevControls;

>

DevControls = new ArrayList();

>

DevControls.Add (typeof(System. Windows.Forms.T extBox));

>

DevControls.Add (typeof(System. Windows.Forms.C omboBox));

>

Type oType = oControl.GetTyp e();

>

for (int cnt = 0; cnt<DevControls .Count; cnt++)

>

{

>

if (DevControls[cnt] == oType)

>

{

>

// This line below is the question... is there a way to
code this ?

>

( (DevControls[cnt]) oControl).ReadO nly = true;

>

}

>

}

I have posted code before that do that; recursively evaluate complex
expression like Class.SubClass1 .Subclass2.Prop erty

This is the relevant part fo the code:
int Compare( object x, object y, string comparer)
{
if ( comparer.IndexO f( ".") != -1 )
{
//split the string
string[] parts = comparer.Split( new char[]{ '.'} );
return Compare( x.GetType().Get Property( parts[0]).GetValue(x,
null) ,
y.GetType().Get Property( parts[0]).GetValue(y, null) , parts[1]
);
}
else
{

**Dan Tallent** · Sep 24 '08, 07:35 PM

Re: Casting question

This seems like a good approach, but for some reason its erroring out about
AmbiguousMatchE xception.

I'm going to look into using a recursive approach as suggested by Ignacio
Machin A little worried about
the speed using recursion and reflection.

Should be interesting.. I'll keep you posted.
Dan

"Alberto Poblacion" <earthling-quitaestoparaco ntestar@poblaci on.orgwrote
in message news:%23kCk0llH JHA.1304@TK2MSF TNGP02.phx.gbl. ..

"Dan Tallent" <spam@microsoft .comwrote in message
news:%238sGlUlH JHA.4564@TK2MSF TNGP02.phx.gbl. ..

>>I thought about using reflection, the problem I am having there is the
>>some of the controls I'm working with have "sub-properites".
>>
>Example: The reach the actual property I would write code like this.
>TextBox1.Prope rties.ReadOnly = true;
>>
>I'm not sure how to get to the sub-properties using reflection.

>
No problem. Just repeat the operation twice:
>
Type t1 = oControl.GetTyp e();
PropertyInfo pi1 = t1.GetProperty( "Properties ");
if (pi1!=null)
{
object prop = pi1.GetValue(oC ontrol, null);
Type t2 = prop.GetType();
PropertyInfo pi2 = t2.GetProperty( "ReadOnly") ;
if (p2i!=null)
{
pi.SetValue(pro p, true, null);
}
}
>
>

**Dan Tallent** · Sep 24 '08, 07:55 PM

Re: Casting question

This was a pretty good idea... but I ended up using this code:

Type t1 = oControl.GetTyp e();

if (t1 == typeof(DevExpre ss.XtraEditors. MemoEdit))

{

((DevExpress.Xt raEditors.MemoE dit)oControl).P roperties.ReadO nly = ReadOnly;

Handled = true;

}

if (t1 == typeof(DevExpre ss.XtraEditors. TextEdit))

{

((DevExpress.Xt raEditors.TextE dit)oControl).P roperties.ReadO nly = ReadOnly;

Handled = true;

}

Thanks to everyone for your help. I really wish I could of found a way to
use a variable in place of the actual Control, but time is short and there
is much to do.

Thanks again

Dan

"Ignacio Machin ( .NET/ C# MVP )" <ignacio.machin @gmail.comwrote in
message
news:dd1c4829-437c-4fd8-8ae3-bc82231b3baa@79 g2000hsk.google groups.com...

On Sep 24, 10:23 am, "Dan Tallent" <s...@microsoft .comwrote:

>I have code here that checks the type of an object and then cast it so I
>can
>access its properties. In the simple example below I am accessing the
>ReadOnly property that is unique to textbox controls. This code works
>however I wanted to find out if its possible to write code using a
>collection or array.. see below
>>
>Type oType = oControl.GetTyp e();
>if (oType == typeof(System.W indows.Forms.Te xtBox))
>>
>{
>>
> ((System.Window s.Forms.TextBox )oControl).Read Only == true;
>>
>}

>
A better approach is
TextBox tb = oControl as TextBox;
if ( tb!= null ){
}
>
you can use the same technique if the number of alternatives is nt too
long.
A more general solution would be using a dictionary:
Dictionary< Type, stringwhere the value indicate the name of the
property you want.
You could have:
< typeof(TextBox) , "readOnly"> ;
< typeof(DropDown ), "SelectedIndex" >;
>
Then you have a method that using reflection get the value based on
the dictionary:
>
object o = GetValue( instance, dcitionary[ typeof(oControl]);

**Ignacio Machin ( .NET/ C# MVP )** · Sep 24 '08, 09:45 PM

Re: Casting question

On Sep 24, 3:23 pm, "Dan Tallent" <s...@microsoft .comwrote:

This seems like a good approach, but for some reason its erroring out about
AmbiguousMatchE xception.
>
I'm going to look into using a recursive approach as suggested by Ignacio
Machin A little worried about
the speed using recursion and reflection.
>
Should be interesting.. I'll keep you posted.
Dan
>
"Alberto Poblacion" <earthling-quitaestoparaco ntes...@poblaci on.orgwrote
in messagenews:%23 kCk0llHJHA.1304 @TK2MSFTNGP02.p hx.gbl...
>

"Dan Tallent" <s...@microsoft .comwrote in message
news:%238sGlUlH JHA.4564@TK2MSF TNGP02.phx.gbl. ..

>I thought about using reflection, the problem I am having there is the
>some of the controls I'm working with have "sub-properites".

>

Example: The reach the actual property I would write code like this.
TextBox1.Proper ties.ReadOnly = true;

>

I'm not sure how to get to the sub-properties using reflection.

>

No problem. Just repeat the operation twice:

>

Type t1 = oControl.GetTyp e();
PropertyInfo pi1 = t1.GetProperty( "Properties ");
if (pi1!=null)
{
object prop = pi1.GetValue(oC ontrol, null);
Type t2 = prop.GetType();
PropertyInfo pi2 = t2.GetProperty( "ReadOnly") ;
if (p2i!=null)
{
pi.SetValue(pro p, true, null);
}
}

The recursion will be just a few steps down. Not too much to worry
about

Casting question

Casting question

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