I am new to C# and am working on classes and understanding them. My problem is I am not understanding how to create a Get to retrieve the private variable _yourname and Set to set the private variable _yourname.
namespace WindowsFormsApplication1
{
class InputClass
{
private string _yourName;
public string _banner;
public virtual void GetInfo();
public InputClass(String _banner)
{
_banner = "Enter your name";
}
}
}
Maybe I am using the wrong function to GetInfo. But I am also wondering when I have the GetInfo if in the () I should write _yourname in it.
In C# there are properties, which have the function of public getter and setter methods in other languages:
class InputClass
{
private string _yourName;
public string _banner;
public InputClass(String _banner)
{
this._banner = _banner;
}
public string YourName
{
get { return _yourName; }
set { _yourName = value; }
}
}
But you can use auto properties, if you want:
class InputClass
{
public InputClass(String _banner)
{
Banner = _banner;
}
public string YourName
{
get; set;
}
public string Banner
{
get; set;
}
}
It sounds like you are trying to provide access to the _yourName field. If so then just use a property
class InputClass {
public string YourName {
get { return _yourName; }
set { _yourName = value; }
}
...
}
Now consumers of InputClass can access it as if it were a read only field.
InputClass ic = ...;
string yourName = ic.YourName;
ic.YourName = "hello";
Note: C# provides a special syntax for simple properties like this which are just meant to be wrappers over private fields. It's named auto-implemented properties
class InputClass {
public string YourName { get; set; }
}
You can override getters and settings using the get and set keywords. For example:
class InputClass
{
private string _yourName;
private string _banner;
public YourName
{
get { return _yourName; }
set { _yourName = value; }
}
public Banner
{
get { return _banner; }
set { _banner = value; }
}
public InputClass(String banner)
{
_banner = banner;
}
}
1.) Use properties instead of members, you get a free accessor (get) and mutator (set).
public string YourName { get; set; }
public string Banner { get; set; }
2.) You can take advantage of the default constructor, and declare it on the fly.
//the old way:
InputClass myClass = new InputClass();
myClass.YourName = "Bob";
myClass.Banner = "Test Banner";
//on the fly:
InputClass myClass = new InputClass()
{
YourName = "Bob",
Banner = "Test Banner"
}
Related
I have two classes defined in my solution
public class Registration {
[...]
public list<Account> Accounts {get; set;}
}
public class Account {
[...]
public string Code { get; set; }
public string Name { get; set; }
public string Address { get; set; }
}
In the web service that I am consuming, the following class definitions are available
public partial class VendReg {
[...]
private Payment_Details[] requestDetailsField;
[System.Xml.Serialization.XmlArrayItemAttribute(IsNullable=false)]
public Payment_Details[] RequestDetails {
get {
return this.requestDetailsField;
}
set {
this.requestDetailsField = value;
}
}
}
public partial class Payment_Details {
private string bk_CodeField;
private string bk_NameField;
private string bk_AddressField;
public string Bk_Code {
get {
return this.bk_CodeField;
}
set {
this.bk_CodeField = value;
}
}
public string Bk_Name {
get {
return this.bk_NameField;
}
set {
this.bk_NameField = value;
}
}
public string Bk_Address {
get {
return this.bk_AddressField;
}
set {
this.bk_AddressField = value;
}
}
}
I want to assign Account to Request Details which is an array of Payment_Details. I tried this code below
vendReg.RequestDetails = registration.Accounts.Cast<Payment_Details>().ToArray();
I got invalid cast exception: Unable to cast object of type 'Account' to type 'Payment_Details'
Please guide on what I am not doing right
You need to convert this yourself (or you can look into things like Automapper)
vendReg.RequestDetails = registration.Accounts.Select(acc =>
new Payment_Details {
Bk_Code = acc.Code,
Bk_Name = acc.Name,
Bk_Address = acc.Address
}).ToArray();
I try to assign textbox value to another class, but I do only this in main class :
public string TextBox1Text
{
get { return textBox1.Text; }
set { textBox1.Text = value; }
}
How can I assign this value in second class?
create the same property in the second class and pass it over in the main class:
public class SecondClass
{
public string TextBox1Text { get; set; }
}
public class MainClass
{
SecondClass sc = new SecondClass();
public string TextBox1Text
{
get { return textBox1.Text; }
set { textBox1.Text = value; }
}
public MainClass
{
sc.TextBox1Text = this.TextBox1Text;
}
}
How can I access the custom attribute of the parent or owner object.
Look at the FieldInfo property of the SQLFieldInfo struct
Here's a more detailed program that will compile and run that shows what I need.
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
Employee myclass = new Employee();
// Load from sql server...
myclass.Name = "Alain";
myclass.Age = 51;
//----
MessageBox.Show(myclass.Name.ToString()); // Should return Alain
MessageBox.Show(myclass.Age.FieldInfo.Type.ToString()); // Should output "int"
}
}
// This next class is generated by a helper exe that reads SQL table design and create the class from it
[SQLTableAttribute(DatabaseName = "Employees", Schema = "dbo", TableName = "Employees")]
public class Employee
{
[SQLFieldAttribute(FieldName = "ID", Type = SqlDbType.Int)]
public SQLFieldInfo<int> ID { get; set; }
[SQLFieldAttribute(FieldName = "Name", Type = SqlDbType.NVarChar, Size = 200)]
public SQLFieldInfo<String> Name { get; set; }
[SQLFieldAttribute(FieldName = "Age", Type = SqlDbType.Int)]
public SQLFieldInfo<int> Age { get; set; }
}
public struct SQLFieldInfo<T>
{
private readonly T value;
public SQLFieldInfo(T Value)
{
this.value = Value;
}
public static implicit operator SQLFieldInfo<T>(T Value)
{
return new SQLFieldInfo<T>(Value);
}
public T Value
{
get
{
return this.value;
}
}
public override string ToString()
{
return this.value.ToString();
}
public SQLFieldAttribute FieldInfo
{
get
{
// Need to retreive the attribute class of the parent or declaring member
return null;
}
}
}
// Holds the sql field information
public class SQLFieldAttribute : Attribute
{
public string FieldName { get; set; }
public SqlDbType Type { get; set; }
public bool AllowNull { get; set; }
public int Size { get; set; }
}
// Holds the sql table information
public class SQLTableAttribute : Attribute
{
public string DatabaseName { get; set; }
public string Schema { get; set; } = "dbo";
public string TableName { get; set; }
}
Thank you!
Alain
My data class is as follows (should be fairly translatable to A above):
public class Foo
{
[Argument(Help = "Name", AssignmentDelimiter = "=")]
public string Name
{
get;
set;
}
}
A helper class is responsible of reading attribute values of objects:
static public string GetCommandLineDelimiter<T>(Expression<Func<T>> property)
{
if(property != null)
{
var memberExpression = (MemberExpression)property.Body;
string propertyName = memberExpression.Member.Name;
PropertyInfo prop = typeof(Arguments).GetProperty(propertyName);
if(prop != null)
{
object[] dbFieldAtts = prop.GetCustomAttributes(typeof(ArgumentAttribute), true);
if(dbFieldAtts.Length > 0)
{
return ((ArgumentAttribute)dbFieldAtts[0]).AssignmentDelimiter;
}
}
}
return null;
}
To use it, simply:
string delimiter = GetCommandLineDelimiter(() => myObject.Name);
That will get the attribute value of AssignmentDelimiter on property Name, i.e. "=".
First, MSDN is your friend.
Then, if you want to get the attributes for ancestors just specify true in the inherit flag of the method:
var attribute = typeof(A).GetProperty("myprop").GetCustomAttributes(true)
.OfType<MycustomAttrib>().FirstOrDefault();
This works. I am doing a lazy initialization of a reference to the custom attribute by using reflection to look at all the properties of all the types.
public class MycustomAttribAttribute : Attribute
{
public MycustomAttribAttribute(string name)
{
this.Name=name;
}
public string Name { get; private set; }
}
class A
{
public A() { MyProp=new B(); }
[MycustomAttrib(name: "OK")]
public B MyProp { get; set; }
}
class B
{
private static Lazy<MycustomAttribAttribute> att = new Lazy<MycustomAttribAttribute>(() =>
{
var types = System.Reflection.Assembly.GetExecutingAssembly().DefinedTypes;
foreach(var item in types)
{
foreach(var prop in item.DeclaredProperties)
{
var attr = prop.GetCustomAttributes(typeof(MycustomAttribAttribute), false);
if(attr.Length>0)
{
return attr[0] as MycustomAttribAttribute;
}
}
}
return null;
});
public string MyProp2
{
get
{
return att.Value.Name;
}
}
}
class Program
{
static void Main(string[] args)
{
// Finds the attribute reference and returns "OK"
string name = (new A()).MyProp.MyProp2;
// Uses the stored attribute reference to return "OK"
string name2 = (new A()).MyProp.MyProp2;
}
}
I have a user control and their are many textbox on it. I add this user control to a different project and I can use it, when I write every property on UserControl. I want to set textbox fields of this user control with using a class. These are my codes:
Class:
namespace IEUserControl
{
public class IEValue
{
public string IsEmriNo { get; set; }
public string Nevi { get; set; }
public string BrutKg { get; set; }
public string NetKg { get; set; }
}
}
User Control:
namespace IsEmriUserControl
{
public partial class UC_IsEmri : UserControl
{
public UC_IsEmri()
{
InitializeComponent();
}
//private IsEmriValue _isEmri;
//public IsEmriValue isEmri
//{
// get
// {
// return _isEmri;
// }
// set
// {
// _isEmri = value;
// }
//}
public string IsEmriNo
{
get { return txtIsEmriNo.Text; }
set { txtIsEmriNo.Text = value; }
}
public string Nevi
{
get { return txtNevi.Text; }
set { txtNevi.Text = value; }
}
public string BrutKg
{
get { return txtBrutKg.Text; }
set { txtBrutKg.Text = value; }
}
public string NetKg
{
get { return txtNetKg.Text; }
set { txtNetKg.Text = value; }
}
}
}
When I use properties, I can set textbox values. However I want to set my textbox values with my Class. Can anyone give me an example setting textbox values with using class? Thank you.
Make a method/property like this
public IEValue IE_Value
{
get
{
return new IEValue() {
IsEmrino = txtIsEmriNo.Text,
Nevi = txtNevi.Text,
BrutKg = txtBrutKg.Text,
NetKg = txtNetKg.Text
};
}
set
{
txtIsEmriNo.Text = value.IsEmrino;
txtNevi.Text = value.Nevi;
txtBrutKg.Text = value.BrutKg;
txtNetKg.Text = value.NetKg;
}
}
I have the class PGMain as the SelectedObject in the propertygrid:
[DefaultPropertyAttribute("Basic")]
[Serializable]
public class PGMain
{
private TestClass m_TEST = new TestClass();
[CategoryAttribute("TEST")]
public TestClass TEST
{
get { return m_TEST; }
set { m_TEST = value; }
}
// More members are here
}
Now I would like to expand the members of the TestClass in the PropertyGrid. So I tried the following:
[Serializable]
[DescriptionAttribute("Expand to see the options for the application.")]
[TypeConverter(typeof(ExpandableObjectConverter))]
public class TestClass : ExpandableObjectConverter
{
[CategoryAttribute("test-cat"), DescriptionAttribute("desc")]
public string Name = "";
[CategoryAttribute("test-cat"), DescriptionAttribute("desc")]
public object Value = null;
[CategoryAttribute("test-cat"), DescriptionAttribute("desc")]
public bool Include = true;
public override bool CanConvertTo(ITypeDescriptorContext context, System.Type destinationType)
{
if (destinationType == typeof(TestClass))
return true;
return base.CanConvertTo(context, destinationType);
}
}
The result is that there is an expandable-icon in front of the TestClass in the propertygrid but it can not be expanded. What am I missing?
Just to be clear: I can show expandable members of the PGMain class but NOT expandable members of the members of the PGMain class like the Test-member in PGMain.
Edit:
No I have 2 classes NOT 1.
[DefaultPropertyAttribute("Basic")]
[TypeConverter(typeof(ExpandableObjectConverter))]
public class fooA
{
private fooB m_TestMember = new fooB();
[Browsable(true)]
[CategoryAttribute("Test category"), DescriptionAttribute("desctiption here")] // <<<<< this one works.
[TypeConverter(typeof(fooB))]
public fooB TestMember
{
get { return m_TestMember; }
set { m_TestMember = value; }
}
}
[DefaultPropertyAttribute("Basic")]
[TypeConverter(typeof(ExpandableObjectConverter))]
public class fooB
{
private string m_ShowThisMemberInGrid = "it works"; // <<<<< this doesn NOT work
[CategoryAttribute("Tile"), DescriptionAttribute("desctiption here")]
public string ShowThisMemberInGrid
{
get { return m_ShowThisMemberInGrid; }
set { m_ShowThisMemberInGrid = value; }
}
public override string ToString()
{
return "foo B";
}
}
But I did solve the problem (by coincidence). It appears that public variables are not listed in the propertygrid. It HAVE to be properties with getters and setters. That was the solution. So the above snippet solved the problem. Thanks for your replies anyway :).
Wrong:
[CategoryAttribute("Tile"), DescriptionAttribute("desctiption here")]
public string Name = "";
Good:
private string m_Name = new string();
[CategoryAttribute("Tile"), DescriptionAttribute("desctiption here")]
public string Name
{
get { return m_Name; }
set { m_Name = value; }
}
Sorry I misinterpret the question.
You can find more details on these links
http://msdn.microsoft.com/en-us/library/aa302326.aspx#usingpropgrid_topic6a
http://www.codeproject.com/KB/miscctrl/bending_property.aspx
http://msdn.microsoft.com/en-us/library/aa302334.aspx
Hope it helps :)
UPDATE:
I copied the code from here
And modified like this.
public class SamplePerson
{
public string Name
{
get;
set;
}
public Person Person
{
get;
set;
}
}
And in the form I have done something like
SamplePerson h = new SamplePerson();
h.Person = new Person
{
Age = 20,
FirstName = "f",
LastName = "l"
};
this.propertyGrid1.SelectedObject = h;
And its working for me.
Provide Browsable as false for properties you don't want to display in the property grid.
[Browsable(false)]
public bool Include
{
get;set;
}