I have noticed that all Controls have a Text property. However, the Intellisense doesn't suggest it for NumericUpDown objects. When manually writing it down, it does work and returns the value of the NumericUpDown as a string. Why is that?
The docs show the property defined as:
[BrowsableAttribute(false)]
[BindableAttribute(false)]
public override string Text { get; set; }
The BrowsableAttribute(false) bit (or more likely EditorBrowsableAttribute) is what 'hides' it from Intellisense.
Why does it hide it?
This API supports the product infrastructure and is not intended to be
used directly from your code.
When defining the default value, what is the difference between
[DefaultValue("member")]
public string Role { get; set; }
and
public string Role { get; set; } = "member";
The first is an attribute which can be useful for meta-programming. For example, you might want to remember what the default value is if someone clears an input. It has nothing to do with the C# language itself. It does not modify the value of Role.
The second actually sets the property's value to 'member' in memory.
From the documentation:
A DefaultValueAttribute will not cause a member to be automatically initialized with the attribute's value. You must set the initial value in your code.
In other words, your first example helps tools (like the Windows Forms Designer) to know what the intended default value for a property is. But it does nothing at run-time.
If you want a property to be assigned a default value at run-time, you have to do it yourself, as in the second example you show.
I want the user to select one out of many elements.
So I'm creating a long list of StringElement, each one with a specific caption. Each element is associated with a specific value. My ideas was to set the Value property of the StringElement. However, this makes the value being shown on the right side of the element.
How can I hide this value? I only need it when the user tapped an entry.
Except for the most basic settings-like dialog I end up (90% of the time) defining my own Element types. It solves many issues (like this one) and reduce duplicated code.
So you get something like:
class MyStringElement : StringElement {
public MyStringElement (string caption, string hiddenValue) : base (caption) {
HiddenValue = hiddenValue;
}
public string HiddenValue { get; set; }
}
You might also want to use the caption as the key to (an existing?) Dictionary<string,string> to reduce the memory requirement of each element (depending on how long your list turns out to be). In any case having your own Element type makes it easier to change its storage/behaviour in the future (with minimal impact elsewhere in your code).
I am attempting to find a way to alter the information that is shown in a DataTip in the VS 2010 Debugger. The purpose being that I would like to choose what property value is shown on the initial window of a DataTip.
For example, when hovering over a collection in debug mode I am presented with the Name of the collection followed by its Count property's value.
This is useful information, but when I am hovering over one of my custom objects I am only presented with a path providing the type of object it is (in my case something like BOS.SuggestedOrdersDataEntity.SuggestedOrdersEntity).
I would like to have this initial DataTip window contain the property that I would determine to be the most useful depending on what custom object it is. For instance it could be the case that for an object that is of type SuggestedOrdersEntity it would be more helpful for the DataTip to show the value of its VendorName property in place of BOS.SuggestedOrdersDataEntity.SuggestedOrdersEntity (similar to the way collections show their Count property). The goal is to not have to use the '+' expander to find the current value of the VendorName (or whatever property is most useful).
I would like to be able to alter the DataTips so that I can customize them to immediately show a specific property's value (just like Count shows for collections) without needing to expand and view all the properties.
Does anyone know if this is possible? I've done some researching on DataTips, but nothing I have found discusses customizing them in this way...
You can use the DebuggerDisplay attribute, examples here.
[DebuggerDisplay("{Name} - {StockSymbol}")]
public class Company
{
public string Name { get; set; }
public string StockSymbol { get; set; }
public IEnumerable<Employee> Employees { get; set; }
public Company(string name) { Name = name; }
}
Does anyone know of a good component (C# WinForms) which would allow creating an options (settings) form, given a custom class with a bunch of properties? I am not looking for something shiny, but something merely better than a property grid. I can easily take care of the visual part, but I simply don't want to lose time doing reflection to add and bind controls if it already exists.
I am pretty sure I've seen a Visual Studio options-like form somewhere before, which was created dynamically (with some attributes attached to the properties of the class, to allow grouping and additional info).
[Edit] For example, I might have an options class:
public class Options : SerializableOptions<Options>
{
[Category("General")]
[Name("User name")]
[Description("Some text")]
public string Username { get; set; }
[Category("General")]
[Name("Log in automatically")]
public bool LogInAutomatically { get; set; }
[Category("Advanced")]
// ConnectionType is enum
public ConnectionType ConnectionType { get; set; }
// ...
}
After passing it to this form, it would create two panels ("General" and "Advanced"), with a CheckBox and a TextBox on the first panel, and one ComboBox (with all available enums) on the second panel.
If there isn't such a control, what do you guys use? Manually add, populate, format and bind controls for each option?
I'm not aware of any controls that allow you to do this, but it isn't difficult to do yourself. The easiest way is to create the dialog shell, a user control which acts as the base class for the options "panels", one (or more) attribute to control the name and grouping information, and an interface (which the user control implements).
Each of your custom options panels derives from the user control and overrides some sort of Initialize() and Save() method (provided by the user control). It also provides your attribute (or attributes) that determine the name/grouping information.
In the dialog shell, reflectively inspect all public types from your assembly (or all loaded assemblies) looking for types that implement your interface. As you find a type, get the attributes to determine where to place it in your grouping (easiest thing here is to use a tree view), call Activator.CreateInstance to create an instance of the user control and store it in the Tag property. When the user clicks on an entry in the grouping (a tree node), get the Tag and set the panel which contains the user control to the object in the Tag property. Finally, when the user clicks "OK" on the dialog, loop through the tree nodes, get the Tag property and call the Save method.
Update:
Another option would be to use a property grid control. It doesn't have a "pretty" UI look to it, but it is very functional, already supports grouping by a category attribute, and allows a great deal of flexibility. You could go with a single property grid that shows all of the options, or go with a "hybrid" approach with a tree view that groups by major functions (plugin, capability, etc.), probably based on the type. When the user clicks that node, give the property grid the object instance. The only drawback to this approach is that when changes are made to the property grid values they are "live" in that the underlying property is immediately changed, which means there is no concept of "Cancel" short of saving a copy of each value that could change and performing some type of "reset" yourself.
I don't know if such a control exists, but writing the required reflection code is really not that hard. E.g. something like this:
// the class for which to create an UI
public class MyClass
{
public string Text { get; set; }
public int ID { get; set; }
}
...
// basic reflection code to build the UI for an object
var obj = new MyClass() { Text="some text", ID=3};
foreach (var pi in obj.GetType().GetProperties())
{
var name = pi.Name;
var type = pi.PropertyType;
var value = pi.GetValue(obj, null);
//now setup the UI control for this property and display the value
}
I accidentally found something similar to this, I remebered that I had this problem a while ago and thought I should share it.
Here is a simple example: http://blog.denouter.net/2008/08/simple-reflection-form.html. It uses reflection to create several controls based on object's properties.