Develop Reference

How to get form when it is which is not visible?

I want to get form which is open but hidden. I have tried by this. I get the form but in this case form show and hide within fraction of second. If I skip mfrm.Show(), I don't get MailSynchronize form in Application.OpenForms.
MailSynchronize mfrm = new MailSynchronize();
mfrm.Show();
mfrm.Hide();
I get form by following method.
foreach (Form f in Application.OpenForms) //it will return all the open forms
{
if (f.Name == "MailSynchronize")
{
mfrm = (MailSynchronize)f;
break;
}
}
Can anybody please suggest me how to get open form which is hidden by default and I can get in Application.OpenForms?

If I Hide a form, does it exist in Application.OpenForms?
No, unfortunately if you Hide a form, it will not be present in Application.OpenForms
So how can I open an invisible Form? Also I want it to exists in Application.OpenForms.
If you want to open an invisible Form, and you want it want it to exists in Application.OpenForms, you can use this code instead of simply Show():
var f = new MailSynchronize();
f.Opacity = 0;
f.ShowInTaskbar = false;
f.Show();
How to find that form again?
To get the open instance of form you can use Application.OfType<MailSynchronize>()
var f= Application.OpenForms.OfType<MailSynchronize>()
.FirstOrDefault();
When I found it, How to show it again?
f.Opacity = 1;
f.ShowInTaskbar = true;
f.Show();
How to hide it again?
You should not call Hide() to hide the form because it makes the form to get out of Application.OpenForms, instead you should use this way:
f.Opacity = 0;
f.ShowInTaskbar = false;
Is there another way?
Yes, for example you can create an static property in a class, for example in Program.cs this way:
public static MailSynchronize MailSynchronizeInstance { get; set; }
and the first time you want to open your form, you can assign the instance to this property, and then you can use it using Program.MailSynchronizeInstance to show or hide and you don't need to look in Application.OpenForms or perform a workaround.
Also you can make this property in a singletone way.

EDIT
This should work for your specific case now:
this.Opacity = 0;
this.ShowInTaskbar = false;
When you add these 2 codelines in your MailSynchronize constructor the form will start minimized but will not show in your taskbar, which is essentially the effect you were looking for. Also the form will now popup in your Application.OpenForms Collection.

When form initiallize.
MailSynchronize mfrm = new MailSynchronize();
mfrm.Opacity = 0;
mfrm.Show();
mfrm.Hide();
How to find that form again?
foreach (Form f in Application.OpenForms) //it will return all the open forms
{
if (f.Name == "MailSynchronize")
{
mfrm = (MailSynchronize)f;
break;
}
}
When I found it, How to show it again?
mfrm.Opacity = 1;
mfrm.Show();
Hide again by Button.
mfrm.Hide(); //It will not show form in Application.OpenForms if I hide again by mfrm.Opacity = 0;

use f.Visible (return type is bool)
if it returns false, it means form is hidden. If it returns true then form is visible.

C# Can't change labels and button properties from a dialogbox

I have my main form and a dialogbox which is called from main. In my main form I have a label and a button that which properties I can't change. I'm using Visual Studio 2015, not sure if there is a bug regarding this. I also made sure my label and button are set to public to modify.
Code: (this is from the dialog box, this has a list box the function is triggered at selectindexchange)
else if ((short)lbDiscountTypes.SelectedValue == 2) //Senior
{
frm_Main main = new frm_Main();
main.VAT = false;
main.labelStatus.Text = "NON-VAT (SENIOR)";
main.labelStatus.BackColor = System.Drawing.Color.IndianRed;
main.labelStatus.ForeColor = System.Drawing.Color.WhiteSmoke;
main.btnNonVat.Enabled = false;
main.btnNonVat.BackColor = System.Drawing.Color.SlateGray;
main.btnNonVat.ForeColor = System.Drawing.Color.Navy;
main.labelVatAmount.Text = 0.00m.ToString();
main.Dispose();
//INQUIRE DISCOUNT TYPES
var Discount = GC.CSHR_DiscountTypes.Where(Filter => Filter.DiscountCode == (short)lbDiscountTypes.SelectedValue);
decimal DP = 0.00m;
foreach (var item in Discount)
{
DP = item.DiscountPercentage;
}
foreach (var item in GC.CSHR_SORepo
.Where(Filter => Filter.Machine == MACHINE
&& Filter.SalesOrderNum == SALESORDERNUM
&& Filter.First_SRP == Filter.IMFSRP))
{
item.DiscountAmount = (item.SoldSRP * DP) / 100;
item.TotalAmount = (item.Quantity * item.SoldSRP) - item.DiscountAmount;
item.VATableSalesOnTotalAmount = (item.Quantity * item.SoldSRP) - item.DiscountAmount;
item.VATRate = 0.00m;
GC.SaveChanges();
}
Close();
}
The code below //INQUIRE DISCOUNT TYPES works well but not the one on top.
I've used debug mode to check if the lines are not being skipped over and they aren't.

You should pay attention to:
You are creating a new instance of your main form that you don't need (while it is open behind the dialog), so you need to get it not create a new instance
You are disposing the main form you created. main.Dispose();
In fact you are creating a new instance of main form and assigning values to those controls and then dispose it. While and instance of yor main form that you expect to see changes on it, is open and untouched behind your dialog.
To set value of those controls you can do one of these ways:
Option 1
Make your labelStatus and btnNonVat public. Open your main form in designer and select labelStatus and btnNonVat and in property grid, set Modifier to public. Then write this code:
//var main = Application.OpenForms.OfType<frm_Main>().FirstOrDefault();
var main = (frm_Main)Application.OpenForms["frm_Main"];
main.labelStatus.Text = "NON-VAT (SENIOR)";
main.labelStatus.BackColor = System.Drawing.Color.IndianRed;
main.labelStatus.ForeColor = System.Drawing.Color.WhiteSmoke;
main.btnNonVat.Enabled = false;
main.btnNonVat.BackColor = System.Drawing.Color.SlateGray;
main.btnNonVat.ForeColor = System.Drawing.Color.Navy;
main.labelVatAmount.Text = 0.00m.ToString();
Option 2
Pass an instance of your frm_Main to your dialog and work with it.
Option 3
After closing the dialog, use values from dialog and set values of your main form

Looks like you are trying to create new form using frm_Main main = new frm_Main(); syntax. All you need to do is get the instance of your current form.
var _currentMainForm= Application.OpenForms[0];
or if you have given name to your form
var _currentMainForm = Application.OpenForms["MainFormName"];
Once you get the reference you can perform all your label updates.

The code on top creates a new form, changes the labels and then disposes the form.
I think you should change the labels of the existing form.

Like in the other answer said you are setting properties of controls into a new Form object and not in the form where you come from.
You should pass the form object into the parameters of the dialog, something like:
void myDialog(frm_Main callingForm)
{
callingForm.Textbox1.Text = "abc";
}
And call it from you main form like this
...
myDialog(this);

Windows forms adding the same binding second time causes argument exception

I bind "Enabled" property of button to datasource member. I use Infragistics.Win.Misc.UltraButton control and its method DataBindings.Add( System.Windows.Forms.Binding ). The button is on dialog form. When I open dialog for the first time binding is added ok. After I close dialog and open it second time I get exception in System.Windows.Forms.ControlBindingsCollection.Add(Binding binding), message says that "Enabled" property of button is read-only. How to solve this?
Dialog opening code is like this:
using (PickItemDialog dialog = new PickItemDialog())
{
dialog.ViewModel = new PickItemViewModel();
dialog.ViewModel.Items = new BindingList<T>(records.ToList());
dialog.ViewModel.Title = title;
dialog.ViewModel.Notification = notification;
if (dialog.ShowDialog() == DialogResult.OK)
return (DataItem)dialog.ViewModel.SelectedItem;
}

What button pressed inputbox C#

I am using the input box from visual basic in c# and I couldn't figure out how I know what button has been pressed. The input box return the string that has been written.
How I know if the cancel button has been clicked or the OK button?
Thank you very much for the help, I didn't find the answer :)
This is what I tried:
string notineName = Interaction.InputBox("Enter the notice name:", "Enter notice name", "");
If you have another way to do input box ( I wanted to make my own but I don't know how to return what button has been clicked) please write it here.

If the user clicks Cancel, a zero-length string is returned.
Try having a look at this documentation. MSDN

As an alternative you could use dialog boxes.
InputDialog dialog = new InputDialog("Caption Here", "Label Text Here", "Default Textbox String");
if (dialog.ShowDialog() == DialogResult.OK)
{
string result_text = dialog.ResultText;
// use result_text...
}
else
{
// user cancelled out, do something...
}
Here an enum result determines what button was selected.

string a;
a = Interaction.InputBox("message", "message");
if (a.Length > 0)
{
comboBox2.Items.Add(a);
// ok
}
else
{
// cancel
}

Sharepoint modal dialog from anotother dialog

When a user clicks on my button there appears a SharePoint modal dialog. The popup shows the user a confirmation message. This is already working.
Now I want the following: When the users clicks on the YES button, the first popup closes and and a new modal dialog opens.
Is this possible? And how? Or can i resize the dialog dynamicly when he's already open?
here are my methods to open the dialogs:
function OpenPopup() {
var options = SP.UI.$create_DialogOptions();
options.url = "popup.aspx";
options.width = 230;
options.height = 235;
options.title = "";
options.dialogReturnValueCallback = Function.createDelegate(null, CloseCallbackNew);
SP.UI.ModalDialog.showModalDialog(options);
}
function OpenSecondPopup() {
var options = SP.UI.$create_DialogOptions();
options.url = "popup2.aspx";
options.width = 630;
options.height = 235;
options.title = "";
options.dialogReturnValueCallback = Function.createDelegate(null, CloseCallbackNew);
SP.UI.ModalDialog.showModalDialog(options);
}

Is it not as simple as
Create a copy of your function CloseCallbackNew called CloseCallbackNewSecond
Change OpenSecondPopup to reference this new copy instead of the original
Add a call to OpenSecondPopup at the end of CloseCallbackNew, referencing the dialog result so as to only call it if the user clicked YES
It seems like this should call the second popup when the first is closed.