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Extending ref keyword to another variable

I'm developing wpf application.
I'm trying to pass object by reference using ref keyword and then pass it to another variable in constructor to change it later. But when I change the variable to which I passed the reference in constructor varaible doesn't change outside scope.
To explain, first I create variable and pass it to another window's constructor.
private void LocatonEditButton_Click(object sender, RoutedEventArgs e)
{
var location = new Location(SelectedLocation.Name, SelectedLocation.X, SelectedLocation.Y, SelectedLocation.Update);
//Creating object
var result = new EditWindow(ref location,true).ShowDialog();
//And passing it to another window with ref
}
Here I assign variable to InitialLocation, if I try to change it here it works on outside variable.
public partial class EditWindow : Window
{
public EditWindow(ref Location location, bool isEdit)
{
InitializeComponent();
InitialLocation = location;
//InitialLocation = ref location; //This is what I want my code to do
location.Name = "new"; //this changes varaiable outside scope
}
private Location InitialLocation;
Here I change InitialLocation but change doesn't persits outside the scope.
private void ConfirmButton_Click(object sender, RoutedEventArgs e)
{
InitialLocation = new Location(CurrentLocation.Name, CurrentLocation.X, CurrentLocation.Y, InitialLocation.Update);
//But this doesn't change varaible outside scope
this.Close();
}
I want to keep object that was passed with ref until the window I passed it to is disposed.
Is it possible to do without waiting for closed event?

I suggest to declare InitialLocation as public property.
public partial class EditWindow : Window
{
public EditWindow(Location location, bool isEdit)
{
InitializeComponent();
InitialLocation = location;
location.Name = "new";
}
public Location InitialLocation { get; set; }
private void ConfirmButton_Click(object sender, RoutedEventArgs e)
{
InitialLocation = new Location(CurrentLocation.Name, CurrentLocation.X, CurrentLocation.Y, InitialLocation.Update);
this.Close();
}
}
after editing read the value of that property:
private void LocatonEditButton_Click(object sender, RoutedEventArgs e)
{
var location = new Location(SelectedLocation.Name, SelectedLocation.X, SelectedLocation.Y, SelectedLocation.Update);
var editWindow = new EditWindow(location, true);
var result = editWindow.ShowDialog();
var changedLocation = editWindow.InitialLocation;
}

C# WPF Window with 'out' for one of the parameters

My problem is I have a variable that I need the window to send back, so I am using out to accomplish this. Here is an example of the constructor for the WPF window.
public CustomYesNo(out bool FormFilled)
{
InitializeComponent();
FormFilled = false;
}
The problem i'm having is I want it so one of the other methods in the class will be able to modify the FormFilled variable that gets sent back to the calling class like below.
private void Button_Yes_Click(object sender, RoutedEventArgs e)
{
FormFilled = true;
Close();
}
Obviously the Button_Yes_Click method does not have access to the FormFilled variable, and I am trying to figure out how I could possible change the value of the FormFilled variable from this method since this variable is only in the constructor's scope. Is what I am trying to do possible using 'out' or do I need to go another route?

Try this pattern
Calling Method:
class foo
{
public void bar()
{
DialogForm myDialogForm = new DialogForm();
myDialogForm.ShowDialog();
if (myDialogForm.DialogResult)
{
//Its true
}
}
}
Form window:
public partial class DialogForm : Window
{
public DialogForm()
{
InitializeComponent();
}
void submitButton_Click(object sender, RoutedEventArgs e)
{
this.DialogResult = true;
}
}
The calling method in WPF is slightly different for checking the result:
bool? result = myDialogForm.ShowDialog();
if (result.HasValue && result.Value)

Issues with calling method from another form

I've found some good posts about using methods in other forms and tried to implement them in my code, but I'm getting a null object error (specifically, the frmAddMaterials object is null). Code compiles fine, error occurs when trying to use the create materials button on the second form.
My first form has an array to hold material information. When the user clicks a link on this first form, they are prompted with a second form where they can enter custom material information in the event that the material they are interested in using is not on designed in. Upon clicking "Add material" on form 2, I would like the RefreshMaterials() method on the first form to run, which creates a new entry in the array based on information from the second form.
Form1:
public partial class frmSnapFitMain : Form
{
public frmMat frmAddMaterials;
public Materials[] material = new Materials[20];
Image[] problemtype = new Image[7];
private void linkLabel1_LinkClicked_1(object sender,LinkLabelLinkClickedEventArgs e)
{
frmMat frmAddMaterials = new frmMat(this);
frmAddMaterials.Show();
}
public void RefreshMaterials()
{
material[Materials.MaterialCount] = new Materials(frmAddMaterials.txtName.Text, Double.Parse(frmAddMaterials.txtFlex.Text), Double.Parse(frmAddMaterials.txtFriction.Text), Double.Parse(frmAddMaterials.txtStrain.Text)); //little m, materials here is for specific instance
cboxMatSelect.Items.Add(frmAddMaterials.txtName.Text);
frmAddMaterials.txtName.Text = ""; //reset fields
frmAddMaterials.txtFlex.Text = "";
frmAddMaterials.txtFriction.Text = "";
frmAddMaterials.txtStrain.Text = "";
}
}
Form 2:
public partial class frmMat : Form
{
private readonly frmSnapFitMain _form1;
public frmMat(frmSnapFitMain Form1)
{
InitializeComponent();
this._form1 = Form1;
}
public void btnCreate_Click(object sender, EventArgs e)
{
this._form1.RefreshMaterials();
this.Close();
}
public void frmMat_Load(object sender, EventArgs e)
{
}
}

In the linkLabel1_LinkClicked_1 method you declare a new instance of frmMat. This instance happens to have the same name of the global variable but it is a local one that disappears when you exit from the method.
private void linkLabel1_LinkClicked_1(object sender,LinkLabelLinkClickedEventArgs e)
{
// This is not the global variable frmAddMaterials.
// It is a local one to this method
frmMat frmAddMaterials = new frmMat(this);
frmAddMaterials.Show();
}
Of course this means that in your RefreshMaterials you use the global variable that has never been initialized
You just need to remove the declaration of a local variable and initialize the global one
private void linkLabel1_LinkClicked_1(object sender,LinkLabelLinkClickedEventArgs e)
{
// This initializes the global variable
frmAddMaterials = new frmMat(this);
frmAddMaterials.Show();
}
Said that it is always a good practice to use a 'defensive programming attitude' when using global variables and test if the variable has been correctly initialized.
public void RefreshMaterials()
{
if(frmAddMaterials != null)
{
material[Materials.MaterialCount] = new Materials(.....)
cboxMatSelect.Items.Add(frmAddMaterials.txtName.Text);
frmAddMaterials.txtName.Text = ""; //reset fields
frmAddMaterials.txtFlex.Text = "";
frmAddMaterials.txtFriction.Text = "";
frmAddMaterials.txtStrain.Text = "";
}
}
I also suggest to subscribe to the FormClosing event of frmAddMaterials to set your instance to null when the form closes
private void linkLabel1_LinkClicked_1(object sender,LinkLabelLinkClickedEventArgs e)
{
if(frmAddMaterials != null)
{
frmAddMaterials = new frmMat(this);
frmAddMaterials.Show();
frmAddMaterials.FormClosing += frmMaterialsClosing;
}
}
private void frmMaterialsClosing(object sender, CancelEventArgs e)
{
frmAddMaterials = null;
}
This allows you to restart the 'cycle' because when you click again the linklabel your global variable is null and you could reinitialize it to the new instance created in the linklabel click event handler.

Different parents for new Winform with a single constructor

Im running into a bit of an issue regarding Children and parents.
I have 2 forms which have the same dropdown menus, both of which have the ability to add additional options to them. When the "(add new)" option is selected in any of the combo boxes my third form is loaded which enables the addition of a new option.
This is the code for that third window (as it stands)
public partial class taskNewDropdownEntry : Form
{
taskWindow _owner;
applianceWindow _owner2;
int windowType;
int manufacturer_id;
sqlMod data = new sqlMod();
public int setManufacturerID {get { return manufacturer_id; } set { manufacturer_id = value; } }
public taskNewDropdownEntry(taskWindow owner, int type)
{
InitializeComponent();
this._owner = owner;
this.windowType = type;
}
public taskNewDropdownEntry(applianceWindow owner, int type)
{
InitializeComponent();
this._owner2 = owner;
this.windowType = type;
}
private void taskNewDropdownEntry_Load(object sender, EventArgs e)
{
if (windowType == 1)
{
instructionLabel.Text = "Input the new appliance type below";
}
else if (windowType == 2)
{
instructionLabel.Text = "Input the new manufacturer below";
}
else if (windowType == 3)
{
instructionLabel.Text = "Input the new model below";
}
}
private void btnOK_Click(object sender, EventArgs e)
{
if (windowType == 1)
{
data.insertApplianceType(textField.Text);
_owner.refreshTypeCombo();
}
else if (windowType == 2)
{
data.insertManufacturerSimple(textField.Text);
_owner.refreshManuCombo();
}
else if (windowType == 3)
{
data.insertModelSimple(manufacturer_id, textField.Text);
_owner.refreshModelCombo();
}
this.Close();
}
private void btnCancel_Click(object sender, EventArgs e)
{
this.Close();
}
}
Now, my issue is that the 2 forms that call this third form are different - thus my only thought of how to solve this would be to duplicate some of the code and modify the methods (you can see the second constructor already added).
Instead of having multiple constructors, and duplicated methods (in this class, or in a seperate one) is there a way whereby I can use the same constructor but different owners depending on the form that calls it?

You have too much implementation in your child form. The way I would tackle this is to
Add a property to your child form:
public string InstructionLabel { get; set; }
This allows your parent forms to individually set the label text when instantiating the form, and also set up an event handler for when the form is closing. So your parent form would have code something like
var newItemForm = new taskNewDropdownEntry();
newItemForm.InstructionLabel = "Input the new appliance type below";
newItemForm.FormClosing += new FormClosingEventHandler(ChildFormClosing);
Then somewhere early in your child form's life cycle (FormLoading event) set
instructionLabel.Text = InstructionLabel;
Then also add a property in the child form for
public string NewItem { get; set; }
your child form should set this public property in the btnOK_Click event
private void btnOK_Click(object sender, EventArgs e)
{
this.NewItem =textField.Text;
}
Then your parent form listens for a FormClosing event, and when it hits that event it takes the NewItem text, adds it to the relevant combo and refreshes it. So in the parent form, the handler looks like
private void ChildFormClosing(object sender, FormClosingEventArgs e)
{
sqlMod data = new sqlMod();
data.insertApplianceType(textField.Text);
refreshTypeCombo();
}

Pretty hard to understand the question but code speaks for all.
There are 2 options, worse (because keeping the parent reference is not a good practice first of all):
create an interface that both classes taskWindow and applianceWindow (where is the naming convention for god's sake!) implement, ex
intrerface IRefreshable {
void refreshManuCombo();
}
then constructor and your poperty can have type of IRefreshable
IRefreshable _owner;
public taskNewDropdownEntry(IRefreshable owner, int type)
{
InitializeComponent();
this._owner = owner;
}
better option, use child form events like Closed to implement refreshing logic in parent. You just need to register event handler before showing the form and voila. Check examples here:
https://msdn.microsoft.com/en-us/library/system.windows.forms.form.closed(v=vs.110).aspx
You can also implement your own public form event for more custom usage (ex. DataChanged, ResultGenerated).

How do I pass variables to a buttons event method?

I need to be able to pass along two objects to the method being fired when I click a button. How do I do this?
So far I've been looking at creating a changed EventArgs:
public class CompArgs : System.EventArgs
{
private object metode;
private Type typen;
public CompArgs(object m, Type t)
{
this.metode = m;
this.typen = t;
}
public object Metode()
{
return metode;
}
public Type Typen()
{
return typen;
}
}
But how would I use it? Is it possible to somehow override the click-event of the button to use a custom eventhandler, which takes CompArgs as a parameter?
private void button1_Click(object sender, EventArgs e)
{
Assembly assembly = Assembly.LoadFile(#"c:\components.dll");
int counter = 0;
foreach (Type type in assembly.GetTypes())
{
if (type.IsClass == true)
{
Button btn = new Button();
btn.Location = new Point(174 + (counter * 100),10);
btn.Size = new Size(95, 23);
btn.Name = type.Name;
btn.Text = type.Name;
btn.UseVisualStyleBackColor = true;
this.Controls.Add(btn);
object obj = Activator.CreateInstance(type);
//I need to pass on obj and type to the btn_Click
btn.Click += new eventHandler(btn_Click);
counter++;
}
}
}
And the event-method where I need it:
private void btn_Click(object sender, CompArgs ca)
{
MessageBox.Show((string)ca.Typen().InvokeMember("getMyName",
BindingFlags.Default | BindingFlags.InvokeMethod,
null,
ca.Metode(),
null));
}

Wow, you guys are making this entirely to difficult. No need for any custom classes or method overrides. In this example I just need to pass a tab index number. You can specify whatever you want, so long as your method is expecting that value type.
button.Click += (sender, EventArgs) => { buttonNext_Click(sender, EventArgs, item.NextTabIndex); };
void buttonNext_Click(object sender, EventArgs e, int index)
{
//your code
}

Cant you just set a property or member variable on the form that hosts the button and access these from the button click event?
EDIT: custom button class suggestion after feedback comment (not the same suggestion as above)
class MyButton : Button
{
private Type m_TYpe;
private object m_Object;
public object Object
{
get { return m_Object; }
set { m_Object = value; }
}
public Type TYpe
{
get { return m_TYpe; }
set { m_TYpe = value; }
}
}
Button1Click(object sender, EventArgs args)
{
MyButton mb = (sender as MyButton);
//then you can access Mb.Type
//and Mb.object
}

I'd create a new Button and override the OnClick method. Rather than passing down the EventArgs, pass a new derived class in with your additional members.
On the delegate receiving the event, cast the given EventArgs to the more derived class you're expecting to get, alternatively setup a new Event that will be triggered at the same time when the button is pressed and hook up to that instead to make things more implicit.
Example Code:
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
ButtonEx b1 = new ButtonEx();
b1.OnCustomClickEvent += new ButtonEx.OnCustomClickEventHandler(b1_OnCustomClickEvent);
}
void b1_OnCustomClickEvent(object sender, ButtonEx.CustomEventArgs eventArgs)
{
string p1 = eventArgs.CustomProperty1;
string p2 = eventArgs.CustomProperty2;
}
}
public class ButtonEx : Button
{
public class CustomEventArgs : EventArgs
{
public String CustomProperty1;
public String CustomProperty2;
}
protected override void OnClick(EventArgs e)
{
base.OnClick(e);
if(OnCustomClickEvent != null)
{
OnCustomClickEvent(this, new CustomEventArgs());
}
}
public event OnCustomClickEventHandler OnCustomClickEvent;
public delegate void OnCustomClickEventHandler(object sender , CustomEventArgs eventArgs);
}

You could use the Tag property of the button. You can add a string value to this property from the designer properties window and then pick it up within the handler as so:
private void MyButton_Click(object sender, EventArgs e)
{
string tagValue = ((Button) sender).Tag;
if(tag == "blah")
{
// Do something
}
}

Not sure if this exists in Winforms but it does in WPF: There is a "tag" object on all controls which you can attach any object to. You could save the object that you want to pass and then in the event handler read it back out of the sender object.
private void Button_Click(object sender, RoutedEventArgs e)
{
var note = (sender as FrameworkElement).Tag as Note;
//Do something with note here
}

You can't use your own custom event argument class for a predefined event handler signature. At least, the custom event argument type will never be utilised by any default calls to the handler (which will only ever be of type EventArgs in the case of a button); you could, potentially, call the handler yourself, passing your custom type, however, you would need to have logic in order to cast it back from an EventArgs into that which it had been cast from.
As a possible solution (depending on your situation), consider a composite type to encapsulate the items you require, as with your event argument type, but keep the required instance as an accessible variable which can be utilised from within the event handler, or, at least, by the method/s which the even handler invokes.
For example, define your type...
public class MyType
{
public object AccessibleItem { get; set; }
}
And, in your form class...
private MyType MyTypeInstance = new MyType();
private void Button_Click(object sender, EventArgs e)
{
//here we can set the item, if needs be...
MyTypeInstance.AccessibleItem = new Anything();
//or access the item to use as required...
DoSomeMagicWithMyObject(MyTypeInstance.AccessibleItem);
}
EDIT:
Okay, looking at your current code I can only offer you this for now (it doesn't add the items to the forms control container and it uses a variable iterator within Linq (which I think is either frowned upon or just down-right wrong (?), but hey...):
private void BuildButtonToObjectDictionary()
{
int counter = 0;
var assembly = Assembly.LoadFile(#"c:\components.dll");
var buttonToObjectDictionary = (
from type in assembly.GetTypes()
where type.IsClass && !type.IsAbstract
select new
{
Button = new Button
{
Name = type.Name,
Text = type.Name,
Size = new Size(95, 25),
Location = new Point(175 + (counter * 100), 10),
UseVisualStyleBackColor = true
},
Item = Activator.CreateInstance(type),
Index = counter++
});
}

Would need to see more code to give a better answer, but you could create an event that takes your CompArgs as a parameter and is fired when the buttonEvent is captured

If you open yourForm.Designer.cs file you will see all the code auto generated by VS. Here you can alter the method called when clicking on the button (or add a second method).
this.yourButton.Location = new System.Drawing.Point(211, 51);
this.yourButton.Name = "yourButton";
this.yourButton.Size = new System.Drawing.Size(75, 23);
this.yourButton.TabIndex = 0;
this.yourButton.Text = "yourButton";
this.yourButton.UseVisualStyleBackColor = true;
this.yourButton.Click += new System.EventHandler(this.yourMethodHere(object1, object2);
Hope this helps.