|
how to set an edit box control so that it only receive numbers. I was thinking about using the event key press.
<italic>Work hard and a bit of luck is the key to success. You don`t need to be genius, to be rich.
|
|
|
|
|
you are taling about windows base application or webbased application?
|
|
|
|
|
It`s windows base application.
<italic>Work hard and a bit of luck is the key to success. You don`t need to be genius, to be rich.
|
|
|
|
|
sorry for posting again :
if its web based then try this ..
//client side code ...
function ValidateNum(input,event){
var keyCode = event.which ? event.which : event.keyCode;
if(parseInt(keyCode)>=48 && parseInt(keyCode)<=57){
return true;
}
return false;
}
at server side page load event
write
yourtextboxname.Attributes.Add("onKeyPress","return ValidateNum(this,event)");
|
|
|
|
|
Handle the KeyPress event and set KeyPressEventArg's Handled property to true if the character is non-numeric.
|
|
|
|
|
Just as Font.Height property gets the line spacing, in pixels, of the given font, how to calculate the same when we have an image instead of a text between two lines.
i.e if we insert an image in any document one after another in consecutive lines there is some space between two images. How to get that value ?
---------------------------------------- line 1
(^o^)/ my image
---------------------------------------- line 2
please guide
|
|
|
|
|
here is what I have:
<br />
private frmMain ParentForm<br />
{<br />
get{return (frmMain)this.MdiParent;}<br />
}<br />
<br />
private void frmEventList_Load(object sender, System.EventArgs e)<br />
{<br />
ParentForm.StatusBar = "Searching for events";
LookupEvents(DateTime.Now, DateTime.Now);<br />
ParentForm.StatusBar = "Ready222";<br />
}<br />
using this the Parent forms status bar text does not change. No exception is thrown indiciating that there is somthing wrong with the code. I have just recently had to change over from VB.NEt so it may be something simple.
Thanks for the help
|
|
|
|
|
are u sure ur frmEventList_Load is getting callled? Try putting a break point in the event handler and following ur code. U should see where ur code is failing to do what u expect. What u've posted looks fine but we're missing a lot more that could be wrong.
|
|
|
|
|
I have put the line break in the load event. It steps through fine, but when I call on the StatusBar property in the commend window it says:
error: 'ParentForm.StatusBar' does not exist
but how would the parent mdiForm not exist? Thanks for the help.
|
|
|
|
|
Could you please post the code where u are creating and showing the MdiChild?
|
|
|
|
|
Here is the form load for the mdiParent
<br />
private void frmMain_Load(object sender, System.EventArgs e)<br />
{<br />
StatusBarPanel status = new StatusBarPanel();<br />
status.AutoSize = StatusBarPanelAutoSize.Spring;<br />
sbrStatus.Panels.Add(status);<br />
sbrStatus.ShowPanels = true;<br />
<br />
Form frmEventList = new frmEventList();<br />
frmEventList.MdiParent = this;<br />
frmEventList.WindowState = System.Windows.Forms.FormWindowState.Maximized;<br />
frmEventList.Show();<br />
}<br />
Thanks for the help
|
|
|
|
|
I cant see what is wrong with ur code...at least not to the point where the command line would give u the error ur stating, unless ur querying ParentForm.StatusBar when its out of scope although I doubt that. Whats even wierder is that, if I'm not misunderstanding, when ur application runs, your not getting any exception.
Just to cover all possibilities, I'll ask u to post some more code once again...sorry :p :
Please post ur StatusBar property.
|
|
|
|
|
I have a windows form, with a data grid on it, that contains information pulled from an xml file. I want to be able to detect if anything in the datagrid is edited, but I do not know what the event is called. Thus, if they add a row, edit a cell, or delete a row, I will set a bool variable (isChanged = true). Any help on what the event is called or how this can be acomplished will be appreciated. Thank you.
Keith
|
|
|
|
|
you can iterate through the cells and check a property for which ones have changed. It's not an event though, I found I had to have a 'save' button when I did something like that, then checked the cells for changes.
Christian
I have several lifelong friends that are New Yorkers but I have always gravitated toward the weirdo's. - Richard Stringer
|
|
|
|
|
Do you read the contents from the XML file into a DataTable and set that DataTable as the data source for the DataGrid? If so, the DataTable has a RowChanged event that will be useful.
-- LuisR
Luis Alonso Ramos
Intelectix - Chihuahua, Mexico
Not much here: My CP Blog!
|
|
|
|
|
Hi, yes that is exactly what I do. Thanks for the help guys.
|
|
|
|
|
 Hi everybody!
Maybe there is somebody who can give me a bit of help; I am about to give up:
I need to ‘translate’ in C# the function GetOpenFileName to include a FileOpenDlg in a Dlg template containing other components, but I cannot handle in C# the reference to the Dialog template resource and the call back function.
Below is the code:
[ StructLayout( LayoutKind.Sequential, CharSet=CharSet.Auto )]
public class OpenFileName
{
public int structSize=0;
public IntPtr dlgOwner= IntPtr.Zero;
public IntPtr hInstance=IntPtr.Zero;
public String filter = null;
public String Customfilter= null;
public int maxCustFilter=0;
public int filterIndex=0;
public String file= null;
public int maxFile = 0;
public String fileTitle= null;
public int maxFileTitle= 0;
public String initialDir= null;
public String title = null;
public int flags=0;
public Int16 fileOffset=0;
public Int16 fileExtension=0;
public String defExt= null;
public IntPtr custData=IntPtr.Zero;
public IntPtr fnHook= IntPtr.Zero;
public OFNHookProc fnHook= IntPtr.Zero;
public String TemplateName;//=null;
}
[ DllImport( "Comdlg32.dll", CharSet=CharSet.Auto )]
public static extern bool GetOpenFileName([ In, Out ] OpenFileName ofn );
……..
…….
private void cmdOpenClick(object sender, System.EventArgs e)
{
OpenFileName ofn=new OpenFileName();
ofn.structSize=Marshal.SizeOf(ofn);
ofn.dlgOwner= this.Handle;
ofn.hInstance=IntPtr.Zero;
ofn.filter="Eseguibili (*.exe)\0*.exe\0Text Files (*.txt;*.doc;*.wri)\0*.txt;*.doc;*.wri\0Tutti (*.*)\0*.*\0\0";;
ofn.Customfilter = null;
ofn.maxCustFilter=0;
ofn.filterIndex=0;
ofn.file=new String(new char[_MaxPath]);
ofn.maxFile=ofn.file.Length;
ofn.fileTitle=new String(new char[_MaxFile]);
ofn.maxFileTitle=ofn.fileTitle.Length;
ofn.initialDir="C:\\";
ofn.title="Apri un file";
ofn.flags= OFN_EXPLORER|OFN_ENABLETEMPLATE|OFN_ENABLEHOOK;
ofn.fileOffset=0;
ofn.fileExtension=0;
ofn.defExt= null;
ofn.custData=IntPtr.Zero;
ofn.fnHook=??????????????????????????;
ofn.TemplateName=????????????????????;
bool risp=GetOpenFileName(ofn);
}
Any pretty good ideas? Many tanks in advance!!
mino
mino
|
|
|
|
|
Instead of using P/Invoke, you might read the documentation[^] for the OpenFileDialog component that encapsulates that API and struct. The same is true for the SaveFileDialog.
In .NET, you can set the fnHook to a delegate but you must declare the struct field as a delegate that matches the necessary signature:
struct OPENFILENAME
{
public OfnHookProc lpfnHook;
}
[return: MarshalAs(UnmanagedType.SysUInt)]
delegate IntPtr OfnHookProc(IntPtr hdlg,
[MarshalAs(UnmanagedType.U4)] int uiMsg, IntPtr wParam, IntPtr lParam);If you don't actually need to use a hook proc to handle your own dialog you don't need ot set this.
For the template name, it's quite a bit harder. The easiest way is to create a native DLL with the resource template - if you even need one, which is merely to extend the dialog itself, which is another reason for using a hook proc - and set the hInstance field to an IntPtr for the native DLL, which you can get using LoadLibrary or LoadLibraryEx. Set the lpTemplateName field to the name of the resource in that native DLL.
Again, though - unless you actually have to extend the UI for the default Open or Save file dialogs, just use the OpenFileDialog and SaveFileDialog components. That's why they're there and don't require your assembly to be granted a privilege to call unmanaged code.
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]
|
|
|
|
|
Hello!
I've been programming in C# for about a month now with a book called Beginning Visual C#.NET (Wrox Press). So yesterday I got to the Events chapter and...
I really need your help!
In this book the author sais and explains that events are used with delegates.
So you kind of use both...
But I can't get it: why are they used with delegates? How do you put them together?
I can undestand events like this (used from a thread nearby...) with no problems:
private void AddButtons()
{
Button B1 = new Button();
B1.Text = "OK";
B1.Location = new System.Drawing.Point(8,8);
B1.Click += new System.EventHandler(buttonB1Click);
}
private void buttonB1Click(object sender, System.EventArgs e)
{
MessageBox.Show("Hello");
}
------
I can understand delegates like this (example from my book):
class Class1
{
delegate double processDelegate(double param1, double param2);
static double Multiply(double param1, double param2)
{
return param1 * param2;
}
static double Devide(double param1, double param2)
{
return param1 * param2;
}
///
/// The main entry point for the application.
///
[STAThread]
static void Main(string[] args)
{
processDelegate process;
Console.WriteLine("Enter 2 numbers separated with a comma:");
string input = Console.ReadLine();
int commaPos = input.IndexOf(',');
double param1 = Convert.ToDouble(input.Substring(0, commaPos));
double param2 = Convert.ToDouble(input.Substring(commaPos + 1,
input.Length - commaPos - 1));
Console.WriteLine("M for multiply, D for devide:");
input = Console.ReadLine();
if (input == "M")
process = new processDelegate(Multiply);
else
process = new processDelegate(Devide);
Console.WriteLine("Result {0}", process(param1, param2));
}
}
}
-----------------------
But I CANNOT undestand what do they have to do with each other? Why use them, when I can use events like in the example above? What do delegates do that helps with events?
Please, explain thoroughly in a non-article dummy-undestandble way, as I have read a lot of articles on it today, but still it seems that in all of them it's a given...
Please! Because I really need to move on, but I can't since I cannot undestand
the topic!
If you want, I can kindly 'reward' you with a Gmail account, no probs with that! But please help!
Thanks!
|
|
|
|
|
Here's a description of delegates and events:
Events and Delegates on MSDN[^]
Basically, by adding an event handler to an event you subscribe your listener to be informed when the particular event occurs.
Your class is informed by the event source by calling your delegate function when the event occurs.
For the event source class to be able to call your function it has to know what parameters an event handler function expects. That's why delegates have to be declared.
Think of delegates as type safe function pointers.
mav
|
|
|
|
|
Damn... maybe I am just hopelessly stupid today (and yesterday) but I still can't get the hang of it... Everything seems to be perfectly clear from your explanation, but somehing is still missing. Sorry  And C# is my first language, so I don't know C++ with function pointers...
Thanks for the reply anyway. Need a Gmail account? Just send me a Email to gbelov@gmail.com and you'll have it!
Anyone else to help a dumb hopeless comedian calling himself a C# programmer?
|
|
|
|
|
Ok, lets see if I can explain myseflt:
Basically, an Event needs a delegate of the method its supposed to call when the event fires.
In your example:
private void AddButtons()
{
Button B1 = new Button();
B1.Text = "OK";
B1.Location = new System.Drawing.Point(8,8);
B1.Click += new System.EventHandler(buttonB1Click);
}
private void buttonB1Click(object sender, System.EventArgs e)
{
MessageBox.Show("Hello");
}
u are using a delegate although you might not be aware of it. The delegate type is:
public delegate void EventHandler(object sender, System.EventArgs e);
and the instance is pointing at buttonB1Click(object sender, System.EventArgs e)
if u dont see it too clearly, use intellisense and create a new instance of the delegate:
EventHandler handler=new EventHandler(.....);
Anyway, u will see this more clearly when u try to create ur own Events for your own classes.
|
|
|
|
|
Hi...
My code look like this...
private void AddButtons()
{
Button B1 = new Button();
B1.Text = "OK";
B1.Location = new System.Drawing.Point(8,8);
B1.Click += new System.EventHandler(buttonB1Click);
}
private void buttonB1Click(object sender, System.EventArgs e)
{
MessageBox.Show("Hello");
}
This works just fine..
But then i want to add some more information when the button is clicked. I want it to look something like this...
private void ButtonB1Click_New(object sender, System.EventArgs e, int something, bool whatever)
{
MessageBox.Show("Hello");
}
Then my question is...
How do I set ButtonB1Click_New to the .Click event?
Thanks
QzRz
QzRz
|
|
|
|
|
I think you have a misconception of what event handlers are.
An event handler is just a callback (look up 'delegate' on MSDN) that is called by the class that publishes the event.
Each event handler has a certain signature, usually containing the object calling the delegate and an additional object holding some additional information for the event.
The Click event of System.Windows.Forms.Button (or rather the matching event handler delegate System.EventHandler) has such a signature. Because System.Windows.Forms.Button calls the delegate you give it, there's nothing you can do to modify the signature of the delegate there.
So you'd have to derive from Button and override the Click event not to require an event handler of type EventHandler but one of type MyNewEventHandler.
This delegate would be declared like this:
public delegate void MyNewEventHandler(object sender, System.EventArgs e, int something, bool whatever);
In your derived class you'll have to fire your new Click event by calling the event handlers attached to your new button class.
You see, it's not quite as easy as you might expect.
Are you sure your button can (or should) provide the additional information in the Click event? Are something and whatever really different with each click?
If not then you shouldn't change the event handler signature for something as basic as a click event.
Mav
|
|
|
|
|
An easier way is to keep the parameters something and whatever, for example, as fields in your class. In your current example, the handler is executed in the same thread and on the same instance so storing this data as fields on your class isn't a problem. This would be a much simpler way of doing it - and is very common through both the .NET BCL and many other applications - than defining your own event for a Button derivative.
Other than that, mav.northwind is right. A handler must use the same signature as the delegate that defines the event.
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]
|
|
|
|
General 
News 
Suggestion 
Question 
Bug 
Answer 
Joke 
Praise 
Rant 
Admin 
Submit an article or tip
