I'm trying to use only Alphanumeric characters an must use 4. No more or less.
The Code I'm using is below. If I remove the For Loop and can type Alphanumeric values in the textbox but I can seem to type only 4 characters. maxLenght says: cannot convert type in to bool. (Must be 4 characters). I appreciate your help.
//string value;string s = BacBox.Text;
int maxLenght = 4;
Regex r = new Regex("^[a-zA-Z0-9]*$");
for (int i = 0; i = maxLenght; i++)
BacBox.Text = s;
MessageBox.Show("Enter 4 alphanumeric characters only");
Thank you for your reply Eddy.
Actually I had already tried this approach but I cannot get the "System.Windows.Forms" using directive not grayed. The event on clicked item method is likned to SelectedItemChanged PropertyThis might be for you a basic issue to deal with?
Consequently I get an error message about a missing definition for "SelectedNode" property.
I have opened a project of mine and promptly stumbled over an old sin: A virtual method call in a constructor. The project involves a DIY UI that runs in a 3D engine and the virtual method call is needed in the constructor of the controls.
It works like a charm, but calling a virtual method in a constructor may cause trouble and I want to get rid of the warning. If you want to take a look: Video clickbait[^]
The problem is that I can't find a way around that virtual method when initializing the properties of a control. I can only do that in the constructor because the view layout is loaded from XAML, like this:
When a control is loaded this way, the constructor must do the following things before the properties are set by the XAML parser:
1) Set the default value for each property
2) Set the values from a control style, if one has been defined
3) Set the values from a named style, if one has been set for this control
The constructor of the base is simple enough:
m_oUserInterface = null;
InitializeDefaultProperties(); // This line is the problem
Calling InitializeDefaultProperties() ensures that the whole procedure is done for all properties of the topmost derived class, including the inherited ones. The derived controls have no own constructors that could interfere. That's why this works perfectly. I just don't see a way to get around calling InitializeDefaultProperties().
I think I got it. It took only a few hours of refactoring, headscratching and debugging. The virtual method call (plus some hidden ones) are gone. Now every control has a proper constructor, like this:
InitializeDefaultProperties() is now a normal private method that simply sets the default values for the properties, just as SetStyle() now only takes the for the class relevant values from the style object.
The magic happens in GetControlStyle(), which has the hard job of figuring out which styles have to be applied. Thank god for reflection! Since each class in the hierarchy now can find what it needs, there is no more need for constructing the controls top down (= no more virtual calls).
Now I have one control left that does not look right, but that will probably only take some more more debugging.
Thanks for the moral support. I knew you were all with me. Silently.
I have lived with several Zen masters - all of them were cats.
I will try to provide additional data concerning the issue I'm dealing with.
I have a root List called "eqtlist" which is composed of items called eqtlist1. Each eqtlist1 contains itself another List (eqtlist2). And each eqtlist 2 is composed of items called eqtlist3.
The idea is to build a treeview containing the details of that implementation. For that purpose, I need to access individually each item of that collection in order to get its name which will be displayed as an item of the treeview.
All this information is stored in a library called EqtListDataBase. My code allows me to access the first (eqtlist) and the second (eqtlevel1) levels. But when trying to go further, I get the NullReference error.
But when trying to go further, I get the NullReference error.
Which you need to investigate; one of those objects you are referencing on that line does not exist. Meaning it results in "null" and not in an object you expect.
Taking the usual suspects, "EqtListDataBase" could throw such an exception, but is probably initialized correctly, otherwise it would have crashed sooner. If the length of the array was incorrect, is would have crashed on the previous line.
What is the method called "GetSetOfEqtLevel2" returning? An array?
Bastard Programmer from Hell
If you can't read my code, try converting it here[^]
Last Visit: 31-Dec-99 18:00 Last Update: 27-Sep-23 15:37