Develop Reference

How to add a custom view dynamically to a view in Visual Studio for Mac C#

I'm working through a project where I'm going to have multiple square size instances of the same set of form components.
I can either create 8 instances manually in my form UI or what I'd rather do is create a view (or Item Renderer) and then dynamically add instances of that view to my main view.
How do I add a create and add a custom view dynamically to the main view in my Xamarin form?
Note: Including Swift tag because you might know the answer if you know Swift or Objective C since the API wraps Apple API.
If IIUC:
Create a view in XCode Interface Builder
In ViewDidLoad create an instance of the custom instance views
Add each instance to the main view
I'd read a guide if there was one but I can't find anything specifically on this.
Some what related. I can create a new View in Xcode interface Builder pretty easily. Is there a way to export that as a class to my application?
Update:
I've found a textfield in Interface Builder where I can enter the name of a class. Back in Visual Studio my main View Controller can see the HelloWorld class. I've found a method named AddChildViewController. I try testing it. Nothing happens. Do I need to set the position and size? I can't find any API to do this.
Tomorrow I will scour the ancient texts again for example code. Maybe there is something I missed?
public override void ViewDidLoad()
{
base.ViewDidLoad();
var view = new HelloView(this.Handle);
var handle = view.Handle;
base.AddChildViewController(view);
var view2 = new HelloView(this.Handle);
handle = view.Handle;
base.AddChildViewController(view2);
}
I noticed a note in the console log:
<ViewController: 0x600000a94180> already have child of:
<ViewController: 0x600000a94180>
Update II:
This adds a new NSView and then a NSButton in that view to the main window:
var frame = new CoreGraphics.CGRect(0, 0, 100, 100);
var button = new NSButton(frame) {
Title = "My Button",
};
var view = new NSView(frame) {};
view.AddSubview(button);
View.AddSubview(view);
It doesn't add my custom class yet though.
Update III:
I'm able to add the custom HelloWorldView class but the controls are not visible. If I add a button to the form I see it but it is anchored to the bottom of the screen. I don't see the controls created from Interface Builder.
//var frame = this.View.Frame;
var frame = new CoreGraphics.CGRect(0, 0, 100, 20);
var button = new NSButton(frame) {
Title = "My Button"
};
var frame2 = new CoreGraphics.CGRect(0, 0, 100, 100);
var helloView = new HelloView() {
};
helloView.Frame = frame2;
helloView.AddSubview(button);
mainFrame.AddSubview(helloView);
HelloView.cs:
public partial class HelloView : NSView
{
public HelloView () : base ()
{
}
}
Note about the code above: I removed the handle parameter because it was causing a compiler error.
Setup: Visual Studio for Mac using Xamarin C# and XCode Interface Builder
--
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How do I navigate to another page from another c# class

I have a main page which has a play, options and exit button, both the play and exit button work as I followed a tutorial on it however for the options button I do not know how to navigate it. What I am planning to do is to create another class called optionsMenu.cs and have like a credits screen or a how to play guide on it.
These are the codes that I have for my options button.
var optionsGameButton = new Button(buttonTexture, buttonFont)
{
Position = new Vector2(300, 250),
Text = "Options",
};
optionsGameButton.Click += OptionsGameButton_Click;
_components = new List<Component>()
{
titleGameButton,
playGameButton,
optionsGameButton,
exitGameButton,
};
Finally I know I have to write a code in this area to be able to get the options button working but I don't know which kind of code to put.
private void OptionsGameButton_Click(object sender, EventArgs e)
{
Console.WriteLine("Credits");
}

If you're set on using click events, then you'll need to create a new instance of your options page and set it as the content of your control object within OptionsGameButton_Click. On the options page you'll need to set the xmlns to your optionsMenu.cs file.
I think you could also set the content of your control object by passing it as a parameter within the method itself, but I've only done this using the ICommand interface.

How to change the title of Timepicker and localization in custom renderer

I have Xamarin forms time picker following custom renderer for IOS
[assembly: ExportRenderer(typeof(TimePicker), typeof(Time24PickerRenderer))]
namespace LabOraTimeStamp.iOS.Renderers
{
public class Time24PickerRenderer:TimePickerRenderer
{
protected override void OnElementChanged(ElementChangedEventArgs<TimePicker> e)
{
base.OnElementChanged(e);
var timePicker = (UIDatePicker)Control.InputView;
timePicker.Locale = new NSLocale("no_nb");
//Get the Done button
var toolbar = (UIToolbar)Control.InputAccessoryView;
var doneBtn = toolbar.Items[1];
//Set the Done to OK
doneBtn.Title = "OK";
}
}
}
I wanted to change the default "done" to "Ok".
1) How can I do that? the line mentioned above for setting the title does not affect anything.
2) I already implemented localization for xamarin forms.I just wanted to use existing Resx values from custom renderer to show the string for appropriate culture.How can I achieve that?

So the reason why your code isn't working is because the done button is created with the UIBarButtonSystemItem.Done style. It doesn't care about the Title property. Renderer code here.
To work around that issue you could try replacing the Xamarin created done button with your own custom Ok button.
//Get the Done button
var toolbar = (UIToolbar)Control.InputAccessoryView;
// Replace Xamarin's buttons with custom ones.
var spacer = new UIBarButtonItem(UIBarButtonSystemItem.FlexibleSpace);
var doneButton = new UIBarButtonItem();
doneButton.Title = "OK";
doneButton.Clicked += (o, a) => Control.ResignFirstResponder();
toolbar.SetItems(new [] { spacer, doneButton}, false);

How to add a ListBox programmatically in a Form

I started out C# very recently and sorry if this question sounds dumb.
How do I add a Listbox in a Form that pops out from a Button click?
Note: The Form isn't the one that's added from the Solution Explorer whereby I can just drag a Listbox from the Toolbox to my Form.
So what I want is to create a ListBox in my file drawer1Form where I can add additional items. Thanks for the help in advance!:)
private void drawer1button_Click(object sender, EventArgs e) // Drawer 1 Button
{
drawer1Form df1 = new drawer1Form();
df1.StartPosition = FormStartPosition.CenterScreen;
df1.Show();
}
public partial class drawer1Form : Form // Creates drawer1Form
{
public drawer1Form()
{
Text = "Drawer 1 ";
}
}

Pretty much the same way as you'd do with any other object.
In the class of your form add a
private ListBox myAwesomeListBox;
Then in the button event handler add something like this:
myAwesomeListBox = new ListBox();
myAwesomeListBox.SuspendLayout();
// set all the properties that you want
myAwesomeListBox.Name = "myAwesomeListBox";
myAwesomeListBox.Location = new Point(...); // place it somewhere
myAwesomeListBox.Size = new Size(...); // give it a size
// etc...
df1.Controls.Add(myAwesomeListBox);
myAwesomeListBox.ResumeLayout();
This should be it.
I highly advise you to do it through the designer first though, and then take a look at the generated code in the form's .Designer.cs file, you'll have a very good understanding after reading through that.

The BindingList Datasource of a Combobox refreshes correctly but the Combobox displays items in the wrong order

I have a BindingList< KeyValuePair < string, string > > that is bound to a ComboBox control. Based on some conditions, the BindingList will be added a new KeyValuePair. Now, the Newly added item shows up at index 0 of the Combobox, instead of at the end.
While debugging, I found that the BindingList has got the right order. (i.e, the new KeyValuePair is appended)
Also, I check the SelectedValue of the ComboBox in it's SelectedIndexChanged handler and it seems to be not of the ListItem that got selected. Instead, it is that of the supposed ListItem, if the ComboBox had got the right order as in its DataSource, - the BindingList..
The code is a small part of a large project.. Plz let me know if the question is not clear. I can put the relevant parts of the code as per our context.
How could something like this happen? What can I do differently?
I have this class something like this.
public class DropdownEntity
{
//removed all except one members and properties
private string frontEndName
public string FrontEndName
{
get {return this.frontEndName; }
set {this.frontEndName= value; }
}
//One Constructor
public DropdownEntity(string _frontEndName)
{
this.FrontEndName = _frontEndName;
//Removed code which initializes several members...
}
//All methods removed..
public override string ToString()
{
return frontEndName;
}
}
In my windows form, I have a tab control with several tabs. In one of the tabs pages, I have a DataGridView. The user is supposed to edit the cells and click on a Next - button. Then, some processing will be done, and the TabControl will be navigated to the next tab page.
The next tab page has the combobox that has the problem I mentioned. This page also has a back button, which will take back.. the user can modify the gridview cells again.. and click on the next button. This is when the order gets messed up.
I am posting here the Click event handler of the Next Button.. Along with the class, with the rest of the code removed.
public partial class AddUpdateWizard : Form
{
//Removed all members..
BindingList<KeyValuePair<string, string>> DropdownsCollection;
Dictionary<string, DropdownEntity> DropdownsDict;
//Defined in a partial definition of the class..
DataGridView SPInsertGridView = new DataGridView();
ComboBox DropdownsCmbBox = new ComboBox();
Button NextBtn2 = new Button();
Button BackBtn3 = new Button();
//Of course these controls are added to one of the panels
public AddUpdateWizard(MainForm mainForm)
{
InitializeComponent();
DropdownsDict = new Dictionary<string, DropdownEntity>();
}
private void NextBtn2_Click(object sender, EventArgs e)
{
string sqlArgName;
string frontEndName;
string fieldType;
for (int i = 0; i < SPInsertGridView.Rows.Count; i++)
{
sqlArgName = "";
frontEndName = "";
fieldType = "";
sqlArgName = SPInsertGridView.Rows[i].Cells["InsertArgName"].Value.ToString().Trim();
if (SPInsertGridView.Rows[i].Cells["InsertArgFrontEndName"].Value != null)
{
frontEndName = SPInsertGridView.Rows[i].Cells["InsertArgFrontEndName"].Value.ToString().Trim();
}
if (SPInsertGridView.Rows[i].Cells["InsertArgFieldType"].Value != null)
{
fieldType = SPInsertGridView.Rows[i].Cells["InsertArgFieldType"].Value.ToString().Trim();
}
//I could have used an enum here, but this is better.. for many reasons.
if (fieldType == "DROPDOWN")
{
if (!DropdownsDict.ContainsKey(sqlArgName))
DropdownsDict.Add(sqlArgName, new DropdownEntity(frontEndName));
else
DropdownsDict[sqlArgName].FrontEndName = frontEndName;
}
else
{
if (fieldType == "NONE")
nonFieldCount++;
if (DropdownsDict.ContainsKey(sqlArgName))
{
DropdownsDict.Remove(sqlArgName);
}
}
}
//DropdownsCollection is a BindingList<KeyValuePair<string, string>>.
//key in the BindingList KeyValuePair will be that of the dictionary.
//The value will be from the ToString() function of the object in the Dictionary.
DropdownsCollection = new BindingList<KeyValuePair<string,string>>(DropdownsDict.Select(kvp => new KeyValuePair<string, string>(kvp.Key, kvp.Value.ToString())).ToList());
DropdownsCmbBox.DataSource = DropdownsCollection;
DropdownsCmbBox.DisplayMember = "Value";
DropdownsCmbBox.ValueMember = "Key";
//Go to the next tab
hiddenVirtualTabs1.SelectedIndex++;
}
private void BackBtn3_Click(object sender, EventArgs e)
{
hiddenVirtualTabs1.SelectedIndex--;
}
//On Selected Index Changed of the mentioned Combobox..
private void DropdownsCmbBox_SelectedIndexChanged(object sender, EventArgs e)
{
if (DropdownsCmbBox.SelectedValue != null)
{
if (DropdownsDict.ContainsKey((DropdownsCmbBox.SelectedValue.ToString())))
{
var dropdownEntity = DropdownsDict[DropdownsCmbBox.SelectedValue.ToString()];
DropdownEntityGB.Text = "Populate Dropdowns - " + dropdownEntity.ToString();
//Rest of the code here..
//I see that the Datasource of this ComboBox has got the items in the right order.
// The Combobox's SelectedValue is not that of the selected item. Very Strange behavior!!
}
}
}
}
The very first time the user clicks the Next Button, it's fine. But if he clicks the Back Button again and changes the Data Grid View cells.. The order will be gone.
I know, it can be frustrating to look at. It's a huge thing to ask for help. Any help would be greatly appreciated!
Please let me know if you need elaboration at any part.
Thanks a lot :)

I think you have two problems here.
First, if you want to retain the order of the items you should use an OrderedDictionary instead of a regular one. A normal collection will not retain the order of the items when you use Remove method. You can see more info about this related to List here.
You could use such dictionary like this:
DropDownDict = new OrderedDictionary();
// Add method will work as expected (as you have it now)
// Below you have to cast it before using Select
DropDownCollection = new BindingList<KeyValuePair<string, string>>(DropDownDict.Cast<DictionaryEntry>().Select(kvp => new KeyValuePair<string, string>(kvp.Key.ToString(), kvp.Value.ToString())).ToList());
The second problem could be that you change the display name (FrontEndName) of already existing items, but the key is preserved. When you add a new item, try to remove the old one that you're not using anymore and add a new item.

The Sorted Property of the Combobox is set to True! I didn't check that until now. I messed up. Terribly sorry for wasting your time Adrian. Thanks a lot for putting up with my mess here.. :)