Re: How to Create static Enum like ConnectionState - C# Discussion Boards

10-Dec-04 20:55

Those are duplicates. One is the private field and the other is the public or protected property that exposes the field. Notice the difference in case? The .NET Framework is case-sensitive (despite what you hear about VB.NET, in which case it's only "case-insensitive" because the source editor corrects the case for you at design-time).

Fields should never be exposed publicly, except perhaps for constant values. One common naming convention is for the private fields to use a lower-case letter in the first position while the property that reflects it uses the upper-case notation that is a guideline in the .NET Framework (unlike Java, in which case all members start with a lower-case letter; consistency is very important in Rapid Application Development (RAD) environments).

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Beta 2.0 limitations

Yaakov Davis10-Dec-04 17:46

Yaakov Davis

10-Dec-04 17:46

Hi ALL.

Is there any legal or technical limitations in publishing .Net Beta 2.0 applications?

Yaakov

Re: Beta 2.0 limitations

Heath Stewart10-Dec-04 20:46

How to Create static Enum like ConnectionState

10-Dec-04 20:46

There is a license.txt file in the SDKs after you download and install them. The best way to understand the legal limitations is to read them or have a lawyer read them.

As far as technical limitations, there really aren't any more than any other language. ".NET" is actually Microsoft's implementation of the Common Language Infrastructure (CLI), and only runs on Microsoft Windows platforms (except 9x, which is not supported any more). There are other CLI implementations for other platforms, including Mono, Portable.NET, and dotGNU.

When you use a full-featured language that targets the CLR (Common Language Runtime) like C# (written from the ground-up for .NET and it is an ECMA standard, unlike other languages *cough* VB.NET) there really isn't much you can't do. C# and other managed languages let you call native functions. C# also allows you to use unsafe code (i.e., direct memory addressing and pointer math with pinned memory).

Once again, the best way to understand the limitations is to read. In this case, be sure to read through the .NET Framework SDK, which is installed by default with VS.NET, available separately as an SDK install, and available online at http://msdn.microsoft.com/library[^]. For 2.0 beta, you'll want to visit http://msdn2.microsoft.com/library[^]. I'll warn you that a lot is not documented publicly yet so the latter reference may not be a lot of help.

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Developer Division Sustained Engineering
Microsoft

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Re: Beta 2.0 limitations

Yaakov Davis10-Dec-04 22:22

Yaakov Davis

10-Dec-04 22:22

Thanks for your detailed answer.

Yaakov

trevor_ledet10-Dec-04 15:21

trevor_ledet

10-Dec-04 15:21

How do you create a stand alone static enum (I guess class) that can be accessed through it's Namespace. Like for instance....

Like in the Namespace System.Data the enums

ConnectionState
CommandType
DataRowAction

In these instances when I want to check a connection's state I compare my connection object's State property to (With no using statement) System.Data.ConnectionState.Open

How do I create a custom enum class inside by Namepsace that I can reference directly without having to reference through a created object?

Thanks for the help!

Trevor Ledet Newbie.

Re: How to Create static Enum like ConnectionState

Heath Stewart10-Dec-04 20:51

Re: How to Create static Enum like ConnectionState

10-Dec-04 20:51

I'm not sure I understand what you're asking, but you don't have to reference an enum through an object: in fact, System.Data.ConnectionState.Open includes no objects - only the namespace (System.Data), then the enum (ConnectionState), and finally the enum member (Open). It isn't like many C/C++ enums that are just #defines.

You declare an enum like so:

public enum MyEnum
{
  One,
  Two,
  Three
}

You can also assign specific values to each. If you want to use a flagged enumeration (so you can use bitwise operators on the enum members), attribute it with the FlagsAttribute and - to following naming guidelines to be consistent with the base class library (BCL) - make the enum plural:

[Flags]
public enum MyEnums
{
  One = 1,
  Two = 2,
  Four = 4
}

For more information about this, I highly suggest you read about the Visual C# Language[^], especially the Visual C# Language Specification[^].

This posting is provided "AS IS" with no warranties, and confers no rights.

Software Design Engineer
Developer Division Sustained Engineering
Microsoft

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trevor_ledet11-Dec-04 5:52

trevor_ledet

11-Dec-04 5:52

I did not realize I could declare a enum in the namespace outside any class being defined in the namespace. But it works.

Thanks for the help.

MOVING CHILD WINDOWS IN MDI

Tyrus18210-Dec-04 15:19

10-Dec-04 15:19

hello i am having tons of trouble moving a child window where i want if the user click within that child i want to keep the cursor at the same location on the child however i want to be able to drag the child around basicly i want to keep the mouse at the same position on the child and be able to move the child relative to the form

here is the code im working with

<br />
	private void gripper1_Click(object sender, System.Windows.Forms.MouseEventArgs e)<br />
	{<br />
		dragging = true;<br />
		this.Dock = System.Windows.Forms.DockStyle.None;<br />
			<br />
		Point p1, p2;<br />
		p1 = PointToClient(new Point(e.X, e.Y));<br />
		p2 = PointToClient(Location);<br />
		diff = new Point(p2.X + p1.X, p2.Y+p1.Y);<br />
	}<br />
		<br />
	private void gripper1_MouseMove(object sender, System.Windows.Forms.MouseEventArgs e)<br />
	{<br />
		if(dragging)<br />
		{<br />
			this.Location = PointToScreen(new Point(e.X + diff.X, e.Y + diff.Y));<br />
		}<br />
	}<br />

i have tried every combination of adding and subtracting and PointToScreen and PointToClient
however none work this is the closest it sometimes keeps the pointer within the child but it seems inconsistant please help this is my 3rd post and none of the solutions that have been offered actualy work. PLEASE PLEASE PLEASE HELP ME!

Skynyrd10-Dec-04 16:28

10-Dec-04 16:28

No need to fumble with Screen or Client coordinates. Its all a question of relative distances so your absolute zero really doesnt matter.

See if this works any better. Haven't tested it, but logic says it should work :p (Contrary to what I said above the code includes some Screen / Client coordinates but its not strictly necessary. The sole purpose is to make everything a little fancier detecting when ur trying to move the child form out of it's parent window)

Point mouseDownPos;

protected override void OnMouseDown(MouseEventArgs e)
{
mouseDownPos=Cursor.Position;
Cursor.Clip=new Rectangle(this.MdiParent.PointToScreen(this.MdiParent.ClientRectangle.Location),this.MdiParent.ClientRectangle.Size);
this.Capture=true;
}

protected override void OnMouseMove(MouseEventArgs e)
{
if (this.Capture)
{
Point mousePos=Cursor.Position;
Rectangle rec=this.MdiParent.ClientRectangle;
int cx=mousePos.X-mouseDownPos.X;
int cy=mousePos.Y-mouseDownPos.Y;
this.Location=new Point(this.Left+cx,this.Top+cy);
mouseDownPos=Cursor.Position;
}
}

protected override void OnMouseUp(MouseEventArgs e)
{
Cursor.Clip=new Rectangle(0,0,0,0);
base.OnMouseUp (e);
}

Hope it helps

Tyrus18210-Dec-04 17:03

10-Dec-04 17:03

i tried your code but nothing act6ualy happens

Skynyrd10-Dec-04 17:07

10-Dec-04 17:07

I just tried it and apart from making a small change to make the cursor clipping a little better everything works fine.

P.D. The code is supposed to be implemented in the child form, not in the parent. And of course, I've tested it with an empty form, if ur form has controls, then it wont pick up the mouse events and the code wont do anything. U seem to link the mouse events to an object called gripper. Link the your gripper mouse events instead of the Form's overrides if your form isnt picking up the mouse events.

Tyrus18210-Dec-04 17:15

10-Dec-04 17:15

read my previous response please

Tyrus18210-Dec-04 17:14

10-Dec-04 17:14

actualy i just changed capture to my dragging and it worked however the mouse position does move slightly in relation to the form when i drag it around alot but for the most part it works how i want it to any ideas how to prevent the mouse from drifting off?

Skynyrd10-Dec-04 17:17

10-Dec-04 17:17

I'm not experiencing any mouse drif but I'm testing this with an empty form. If your form has controls that could intercept mouse events and therefore not reaching the form hanlders, it could be cause of a small drift. I'm not too sure about it though.

Check that, I dont think that could be the cause. The only sympton would be that depending where u click, the form would capture the mousedown and move or it wouldn't do anything.

What is ur form's control layout if any?

Tyrus18210-Dec-04 17:29

10-Dec-04 17:29

atm it the form inherats a base class that is a form with a custom gripper control the gripper is the thing actualy is reciving my mouse click and mouse move message the mouse seems to drift when i move the mouse really fast or when i move the window beyond the edge of the visible screen and yes i do have docked control in my parent

what i am trying to do is create my own docking windows so far its going well except for this mouse positon stuff :p

Tyrus18210-Dec-04 17:44

10-Dec-04 17:44

hey on a similar topic how would i determine whether or not my child is at or beyond the parents rectangle
if(this.ClientRectangle.Top <= this.MdiParent.ClientRectangle.Top)
MessageBox.Show("Hi");

i tried this but it always message boxs me no matter where i drop the form

Skynyrd10-Dec-04 19:10

10-Dec-04 19:10

Check my original post. I modified the post and implemented a mouse clipping that prevents u from moving the mouse outside the parentform if a child form is captured.

This only prevents ur mouse exiting the parent form when moving a child. If u want to detect when the child form begins to go past the parent window I would work with screen coordinates similar to what I did with the mouse clipping.

For example: The parent client rectangle in Screen coord would be:

clientRec = new Rectangle(this.MdiParent.PointToScreen(this.MdiParent.ClientRectangle.Location),this.MdiParent.ClientRectangle.Size);

Your child form rectangle (including none client areas) would be:
childRec=new Rectangle(this.PointToScreen(this.Bounds.Location),this.Bounds.Size);

Then it would be a matter of comparing when one crosses over the other. Top, Bottom, Left and Right.

There could be a problem with the parent's client rectangle. Its not always the same size as the MdiChildContainerWindow. Some docked controls like a StatusBar shorten the MdiChildrenWindow but dont afect the form's clientSize.

A way to get around this is to iterate through the control collection of ur parent form until u find the one with the type 'System.Windows.Forms.MdiClient' (You tipically do this after the InitializeComponents method in your constructor and store the MdiClient control in a private class member that u can access whenever u want without having to search through the control collection again and again). This control is automatically added when u set ur form as a MdiContainer. U can then base ur calculations on the MdiClient control's true size and location instead of using the forms ClientRectangle.

Tyrus18210-Dec-04 19:54

10-Dec-04 19:54

i have been able to compare locations thanks to your suggestion and it does work
however toolbars statusbars and docked controls seem to not affect it wahts the easiest way to determen the size of the visible mdi area thats not a docked control/toolbar/statusbar?
i appreciate all your help it has been most usefull

Skynyrd11-Dec-04 2:08

11-Dec-04 2:08

Use the following code in ur Parent form:

private MdiClient myMdiClient;

public ParentForm()
{

InitializeComponent();

foreach (Control ctrl in this.Controls)
{
if (ctrl is MdiClient)
{
myMdiClient=(MdiClient)ctrl;
break;
}
}
}

public Rectangle MdiClientScreenRectangle
{
get
{
return this.RectangleToScreen(myMdiClient.ClientRectangle);
}
}

(I'm supposing u have setted the parent form as a MdiContainer through the designer. If not, run foreach code AFTER setting the IsMdiContainer property to true).

Once u've done this, use the follwing rectangle to compare with ur child form's rectangle:

Rectangle parentRectangle=((ParentForm)this.MdiParent).MdiClientScreenRectangle;

sqlCommand in C#

John L. DeVito10-Dec-04 12:48

John L. DeVito

10-Dec-04 12:48

Heyas all,

I'm attempting to insert data entered into text boxes into a
table. I'm looking at examples and I come across something
like the following

<br />
SqlCommand Command = new SqlCommand("insert into katalog(Program Name, Publisher, Category, Disk Number, Date Added) Values ('value', 'value', 'value', 'value', 'value')", myConnection);<br />

The question is, how would I insert the text currently in the
the textbox? in other words, how do I replace 'value' above with the statement textbox1.text?

thanks all

"There are 10 types of people in this world; Those that know binary and those that do not."

Re: sqlCommand in C#

Heath Stewart10-Dec-04 13:03

CallContext SerializationException

10-Dec-04 13:03

Always use parameterized queries, and for the SQL provider for ADO.NET that's very easy (ADO.NET supports paramterized queries, but some providers provide better support).

For example:

using (SqlCommand cmd = myConnection.CreateCommand())
{
  cmd.CommandText = @"insert into katalog
([Program Name], Publisher, Category, [Disk Number], [Date Added])
values (@name, @pub, @cat, @num, @date)";
 
  cmd.Parameters.Add("@name", SqlDbType.NVarChar, 40).Value = txtName.Text;
  cmd.Parameters.Add("@pub", SqlDbType.NVarChar, 40).Value = txtPub.Text;
  cmd.Parameters.Add("@cat", SqlDbType.NVarChar, 40).Value = txtCat.Text;
 
  try
  {
    cmd.Parameters.Add("@num", SqlDbType.Int).Value = int.Parse(txtNum.Text);
  }
  catch (FormatException)
  {
    MessageBox.Show("Please enter a valid serial number.");
  }
 
  try
  {
    cmd.Parameters.Add("@date", SqlDbType.DateTime).Value = DateTime.Parse(txtDate.Text);
  }
  catch (FormatException)
  {
    MessageBox.Show("Please enter a valid date.");
  }
 
  try
  {
    myConnection.Open();
    cmd.ExecuteNonQuery();
  }
  catch (Exception ex)
  {
    MessageBox.Show("Error: could not update the database.\n" + ex.Message);
  }
  finally
  {
    myConnection.Close();
  }
}

This is a very simplistic example, but you can learn more by reading about ADO.NET in the .NET Framework SDK that was installed by default with Visual Studio .NET or the stand-alone SDK installer, and is available online at http://msdn.microsoft.com/library[^].

Again, note that different providers provide slightly different support for ADO.NET features like parameterized queries and transactions, so be sure to read about the classes under the System.Data namespace, along with its child namespaces.

This posting is provided "AS IS" with no warranties, and confers no rights.

Software Design Engineer
Developer Division Sustained Engineering
Microsoft

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Skynyrd10-Dec-04 12:48

Re: CallContext SerializationException

10-Dec-04 12:48

Hi all. I'm trying to pass some info from the client app to the remote singlecall object via Context, using CallContext.SetData / GetData.

I've created the following ConxtextDataObject:

[Serializable]
public class CallContextData:ILogicalThreadAffinative
{
private string myData;

public CallContextData()
{
}

public string Data
{
get
{
return myData;
}
set
{
myData=value;
}
}

public override string ToString()
{
return myData;
}
}

In my AssemblyInfo file, the only security attribute I've included is:
[assembly: PermissionSetAttribute(SecurityAction.RequestMinimum, Name="FullTrust")]

I go ahead and set the context data, but when I make the remote object call, I always get the following expection: Error message would translate to "Due to security restrictions, the type Vigila.Objects.CallContextData cannot be accessed."

{"Por restricciones de seguridad, no se puede obtener acceso al tipo Vigila.Objects.CallContextData." }
[System.Runtime.Serialization.SerializationException]: {System.Runtime.Serialization.SerializationException}
System.Object: {System.Runtime.Serialization.SerializationException}
_className: "System.Runtime.Serialization.SerializationException"
_COMPlusExceptionCode: -532459699
_exceptionMethod: <undefined value="">
_exceptionMethodString: "8\0GetSafeUninitializedObject\0mscorlib, Version=1.0.5000.0, Culture=neutral, PublicKeyToken=b77a5c561934e089\0System.Runtime.Serialization.FormatterServices\0System.Object GetSafeUninitializedObject(System.Type)"
_helpURL: null
_HResult: -2146233076
_innerException: {"Error de solicitud." }
_message: "Por restricciones de seguridad, no se puede obtener acceso al tipo Vigila.Objects.CallContextData."
_remoteStackIndex: 1
_remoteStackTraceString: "\nServer stack trace: \n at System.Runtime.Serialization.FormatterServices.GetSafeUninitializedObject(Type type)\r\n at System.Runtime.Serialization.Formatters.Binary.ObjectReader.ParseObject(ParseRecord pr)\r\n at System.Runtime.Serialization.Formatters.Binary.ObjectReader.Parse(ParseRecord pr)\r\n at System.Runtime.Serialization.Formatters.Binary.__BinaryParser.ReadObjectWithMapTyped(BinaryObjectWithMapTyped record)\r\n at System.Runtime.Serialization.Formatters.Binary.__BinaryParser.ReadObjectWithMapTyped(BinaryHeaderEnum binaryHeaderEnum)\r\n at System.Runtime.Serialization.Formatters.Binary.__BinaryParser.Run()\r\n at System.Runtime.Serialization.Formatters.Binary.ObjectReader.Deserialize(HeaderHandler handler, __BinaryParser serParser, Boolean fCheck, IMethodCallMessage methodCallMessage)\r\n at System.Runtime.Serialization.Formatters.Binary.BinaryFormatter.Deserialize(Stream serializationStream, HeaderHandler handler, Boolean fCheck, IMethodCallMessage metho
dCallMessage)\r\n at System.Runtime.Serialization.Formatters.Binary.BinaryFormatter.UnsafeDeserialize(Stream serializationStream, HeaderHandler handler)\r\n at System.Runtime.Remoting.Channels.CoreChannel.DeserializeBinaryRequestMessage(String objectUri, Stream inputStream, Boolean bStrictBinding, TypeFilterLevel securityLevel)\r\n at System.Runtime.Remoting.Channels.BinaryServerFormatterSink.ProcessMessage(IServerChannelSinkStack sinkStack, IMessage requestMsg, ITransportHeaders requestHeaders, Stream requestStream, IMessage& responseMsg, ITransportHeaders& responseHeaders, Stream& responseStream)\n\nException rethrown at [0]: \n"
_source: "mscorlib"
_stackTrace: {System.Array}
_stackTraceString: null
_xcode: 0
_xptrs: 0
HelpLink: null
HResult: -2146233076
InnerException: {"Error de solicitud." }
Message: "Por restricciones de seguridad, no se puede obtener acceso al tipo Vigila.Objects.CallContextData."
Source: "mscorlib"
StackTrace: "\nServer stack trace: \n at System.Runtime.Serialization.FormatterServices.GetSafeUninitializedObject(Type type)\r\n at System.Runtime.Serialization.Formatters.Binary.ObjectReader.ParseObject(ParseRecord pr)\r\n at System.Runtime.Serialization.Formatters.Binary.ObjectReader.Parse(ParseRecord pr)\r\n at System.Runtime.Serialization.Formatters.Binary.__BinaryParser.ReadObjectWithMapTyped(BinaryObjectWithMapTyped record)\r\n at System.Runtime.Serialization.Formatters.Binary.__BinaryParser.ReadObjectWithMapTyped(BinaryHeaderEnum binaryHeaderEnum)\r\n at System.Runtime.Serialization.Formatters.Binary.__BinaryParser.Run()\r\n at System.Runtime.Serialization.Formatters.Binary.ObjectReader.Deserialize(HeaderHandler handler, __BinaryParser serParser, Boolean fCheck, IMethodCallMessage methodCallMessage)\r\n at System.Runtime.Serialization.Formatters.Binary.BinaryFormatter.Deserialize(Stream serializationStream, HeaderHandler handler, Boolean fCheck, IMethodCallMessage methodCallMessage)
\r\n at System.Runtime.Serialization.Formatters.Binary.BinaryFormatter.UnsafeDeserialize(Stream serializationStream, HeaderHandler handler)\r\n at System.Runtime.Remoting.Channels.CoreChannel.DeserializeBinaryRequestMessage(String objectUri, Stream inputStream, Boolean bStrictBinding, TypeFilterLevel securityLevel)\r\n at System.Runtime.Remoting.Channels.BinaryServerFormatterSink.ProcessMessage(IServerChannelSinkStack sinkStack, IMessage requestMsg, ITransportHeaders requestHeaders, Stream requestStream, IMessage& responseMsg, ITransportHeaders& responseHeaders, Stream& responseStream)\n\nException rethrown at [0]: \n at System.Runtime.Remoting.Proxies.RealProxy.HandleReturnMessage(IMessage reqMsg, IMessage retMsg)\r\n at System.Runtime.Remoting.Proxies.RealProxy.PrivateInvoke(MessageData& msgData, Int32 type)\r\n at Vigila.Objects.IDataLayerTool.GetAssetsMenuLayout()\r\n at Vigila.Objects.SingleCallManager.RunMethod(String methodName, Object[] arguments) in d:\\proyectos .net\\código aplicacione
s\\vigila 2\\vigila objects\\singlecallmanager.cs:line 113\r\n at Vigila.Client.VigilaStartUp.loadUpIniData() in d:\\proyectos .net\\código aplicaciones\\vigila 2\\vigila client\\vigilastartup.cs:line 62\r\n at Vigila.Objects.ThreadWorker.workingEnvelope() in d:\\proyectos .net\\código aplicaciones\\vigila 2\\vigila objects\\threadworker.cs:line 157"
TargetSite: {System.Reflection.RuntimeMethodInfo}

I've tried demanding a PermissionSecurity with the Infrastructure Flag right before the remote call to see if I would get an exception for not having the required permissions, but that doesnt seem to be the problem.

I'm out of ideas...anybody knows whats going on?

Heath Stewart10-Dec-04 12:54

Re: CallContext SerializationException

10-Dec-04 12:54

In which project's AssemblyInfo.cs file did you add that assembly-level declarative security attribute? The client or the server? If the code even runs at all, it's not a code access security problem. When the CLR loads your assembly it will demand for that permission set. If the demand fails, the assembly is not loaded. It'll never even get to your remoting code. To grant this permission set you'll need to run the client off your local machine (by default, local code runs with FullTrust permissions) or create a code group to grant your code (via whatever evidence seems suitable) the FullTrust permission set.

So, have you tried debugging your code to make sure it's even loading?

This posting is provided "AS IS" with no warranties, and confers no rights.

Software Design Engineer
Developer Division Sustained Engineering
Microsoft

[My Articles] [My Blog]

Skynyrd10-Dec-04 13:12