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How to return to the calling method after calling a windows Form in c#?

I have a method, where I call a new Windows Form in Class A. And in the new Form, I use a Dropdown menu and store the selected Item from the Dropdown in a variable, called selectedItem.Now I have to access this selectedItem in Class A. I use the following code.
public class A
{
public method callingmethod()
{
ExceptionForm expform = new ExceptionForm();
expform.Show();
string newexp = expobj.selectedexception;
}
}
And my code in New Form,
public partial class ExceptionForm : Form
{
public string selectedexception = string.Empty;
private void btnExpSubmit_Click(object sender, EventArgs e)
{
selectedexception = this.comboBox1.GetItemText(this.comboBox1.SelectedItem);
this.Close();
return;
}
}
Now After clicking on Submit button, I get the correct value in selectedItem, But I could not pass it to Class A. How to retun to Class A?

If you are ok with posting ExceptionForm over parent form by disabling it, go for ShowDialog. But, if you do not wish to disable parent for and continue popping ExceptionForm as a new and independent window, try eventing back to parent form. Here I show an example on how to do so:
public partial class ExceptionForm : Form
{
public delegate void SelectValueDelegate(string option);
public event SelectValueDelegate ValueSelected;
private void btnExpSubmit_Click(object sender, EventArgs e)
{
this.Close();
if (this.ValueSelected!= null)
{
this.ValueSelected(this.comboBox1.GetItemText(this.comboBox1.SelectedItem));
}
return;
}
}
And in calling class:
public class A
{
public method callingmethod()
{
ExceptionForm expform = new ExceptionForm();
expform.ValueSelected += ExceptionForm_ValueSelected;
expform.Show();
}
private void ExceptionForm_ValueSelected(string option)
{
string newexp = option;
// Do whatever you wanted to do next!
}
}

Use ShowDialog() method.
expform.ShowDialog();
string newexp = expobj.selectedexception;

how to pass ObservableCollection from one page1 to page2 without use MVVM

I want to pass ObversableCollecion temp from page1 to page2 ,when I click the button in page1.But I don't wan't to use MVVM,just be simnple.My code are as follows:
page1:
public ObservableCollection<Staff> Staff_Collection { get; set; }
private void button_click1(object sender, RoutedEventArgs e)
{
Page1 page1= new Page1();
page1.Staff_Show = Staff_Collection;
this.NavigationService.Navigate(page1);}
page2:
public ObservableCollection<Staff> Staff_Show = new ObservableCollection<Staff>();
public TaxBefore_Sum()
{
InitializeComponent();
DataContext = this;
Staff_Show = new ObservableCollection<Staff>();
}
but it doesn't work.

var whateverPage = new WhateverPage(whateverDataYouWantToPass);
this.NavigationService.Navigate(whateverPage);
Just make sure, the constructor for WhateverPage (the page you are navigating to) is overloaded to accept the item you are passing into it like this:
public WhateverPage(WhateverData data)
{
// code here
}
So in your case, if you are navigating to a page called Page2, then you will create a constructor in that page like this:
public Page2(ObservableCollection<Staff> staff)
{
// Now you have staff in Page2. You can assign it to a property or field
}

Load a method of User Control that is calling in another page (Windows Phone7)

I have a UserControl with name UcMdisaese inside MainPage that execute an animation.
public partial class MDisaese : UserControl
{
Public void Fases(int i)
{
_mdmodel.enojo();
enojado = 0;
_timer1.Interval = TimeSpan.FromSeconds(i);
}
}
Also I have a Page with name "Agrega_m" inside when ocurrs the event guardar_agrega_Click activate the animation I suppose, but doesn't work the method Fases to call the animation when I return to Mainpage that contain the User Control.
The question, How can load the method?
public partial class Agrega_m: PhoneApplicationPage
{
private void guardar_agrega_Click(object sender, EventArgs e)
{
MDisaese hi = new MDisaese();
hi.fases(30);
}
}

What is the recommended way to assign and change an event for button on a form

I have a form which I want to be 'resusable' for a variety of situations. Mostly display and print information. The form has 2 buttons and a listbox
I want to be able to pass an object to the form that tells the form what the buttons are to do when pressed(for example show a MessageBox, Print out the contents of the listbox or close the form)
I am using an if statement to figure out what event to assign to my button...is there a better way to do this?
Ideally I would like to set the event from the initial calling code instead fo using an enum called 'Action'
==========calling code=================
var information = new Information();
information.Action = Action.Print;
var frmInformation = new frmInformation(information);
frmInformation.Show(this);
====================information class======================
public class Information
{
public delegate void OkButtonDelegate();
public IList<string> information{ get; set; }
public Information()
{
information = new BindingList<string>();
}
===============information form======================
public partial class frmInformation : Form
{
private readonly Information _information;
public Information.OkButtonDelegate _delegate;
public frmInformation(Information information)
{
_information = information;
InitializeComponent();
SetupForm();
}
private void SetupForm()
{
if (_information.Action== Action.Print)
_delegate = new Information.OkButtonDelegate(Print);
else if (_information.Action == Action.Close)
_delegate = new Information.OkButtonDelegate(Close);
}
private void ShowMessageBox()
{
MessageBox.Show("lalalalalala");
}
public static void Print()
{
//take the contente out of listbox and send it to the printer
}
private void btnSend_Click(object sender, EventArgs e)
{
_delegate();
}

You may change it this way
switch (_information.Action) {
case Action.Print:
btnSend.Click += (s,e) => Print();
break;
case Action.Close:
btnSend.Click += (s,e) => Close();
break;
}
You won't need delegate type, generated Click handler and _delegate variable.

Data from parent to dialog

I have a parent form and a dialog. I need to pass info from the parent to the dialog
Here's what I have:
private void Item_Click(object sender, EventArgs e)
{
DialogResult result = DialogResult.OK;
DlgGraphOptions _frmDlgGraphOptions = new DlgGraphOptions();
_frmDlgGraphOptions.m_SerOpts = theDGroup.m_SerOpts;
_frmDlgGraphOptions.ShowDialog(this);
if (result == DialogResult.OK)
{
// Save the revised options to the Data Group
theDGroup.m_SerOpts = _frmDlgGraphOptions.m_SerOpts;
}
In DlgGraphOptions(child/dialog) form, I have intialitzed
public partial class DlgGraphOptions : Form
{
public GraphOpts_t m_SerOpts = new GraphOpts_t();
}
private void InitSettings(int idxSeries)
{
m_nMaxPts = m_SerOpts.GetMaxPts(idxSeries);
}
So I need to pass theDGroup.m_SerOpts from parent to the dialog,so I have done
_frmDlgGraphOptions.m_SerOpts = theDGroup.m_SerOpts;
in the parent. Now in the child:
public GraphOpts_t m_SerOpts = new GraphOpts_t;
This seems to be wrong. I don't want to be reinitializing it.

I think you should change your code in this way:
First, in the DlgGraphOptions form, change the constructor of DlgGraphOptions
// Force the caller to pass a GraphOpts_t
// Check if it is a valid instance or create one as new
public partial class DlgGraphOptions(GraphOpts_t input ) : Form
{
m_SerOpts = (input == null ? new GraphOpts_t() : input);
}
then create a public property with only the getter returning the internal GraphOpts
public GraphOpts_t Options
{
get{ return m_SerOpts; }
}
then, in the calling form, change uour code
// Pass the m_setOpts from theDGroup
DlgGraphOptions _frmDlgGraphOptions = new DlgGraphOptions(theDGroup.m_SerOpts);
if(DialogResult.OK == _frmDlgGraphOptions.ShowDialog(this))
{
// Save the revised (or new) options to theDGroup
theDGroup.m_SerOpts = _frmDlgGraphOptions.Options;
}
This approach will force the user of your dialog to pass an initialization value or null.
However your InitSettings will work with a initialized value and you don't have initialized two times your options instance.
(Actually there isn't a big improvement from your code, but I think it is a better approach)

Your child class should probably have the m_SerOpts as a property:
public partial class DlgGraphOptions : Form
{
public GraphOpts_t m_SerOpts { get; set; }
}
Your click event can probably be cleaned up like this:
private void Item_Click(object sender, EventArgs e)
{
using (DlgGraphOptions _frmDlgGraphOptions = new DlgGraphOptions()) {
_frmDlgGraphOptions.m_SerOpts = theDGroup.m_SerOpts;
if (_frmDlgGraphOptions.ShowDialog(this) == DialogResult.OK)
{
// Save the revised options to the Data Group
theDGroup.m_SerOpts = _frmDlgGraphOptions.m_SerOpts;
}
}
}
where in your DlgGraphOptions form, you need to set the form's DialogResult property in the OK or Save button event.
You could also just pass m_SerOpts object through the constructor:
public partial class DlgGraphOptions : Form
{
public GraphOpts_t m_SerOpts { get; }
public DlgGraphOptions(GraphOpts_t serOpts) {
InitializeComponents();
m_SerOpts = serOpts;
}
}