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Is it possible to tell if the Text change on an entry was from code or from the UI?

I am working on a Xamarin project and I need to be able to tell if the changes that occur to the text in an Entry view are from the code or from the UI, is this possible in Xamarin? or is there a known work around to do this.
I know about the OnTextChanged event but this only tells you that the Text property has changed, and gives you access to the old and new value of the Text property. It does not differentiate between different causes of text change.

You can get some idea from this thread, check if the entry is focused to differentiate between different causes of text change:
public MainPage()
{
InitializeComponent();
myEntry.TextChanged += MyEntry_TextChanged;
}
private void MyEntry_TextChanged(object sender, TextChangedEventArgs e)
{
var entry = sender as Entry;
if (entry.IsFocused)
{
//change from UI
Console.WriteLine("change from UI");
}
else{
//change from code
Console.WriteLine("change from code");
}
}
Update: The better way to solve op's problem:
You can set a flag yourself that tells your code to ignore the event. For example:
private bool ignoreTextChanged;
private void textNazwa_TextCanged(object sender, EventArgs e)
{
if (ignoreTextChanged) return;
}
Create a method and use this to set the text instead of just calling Text = "...";::
private void SetTextBoxText(TextBox box, string text)
{
ignoreTextChanged = true;
box.Text = text;
ignoreTextChanged = false;
}
Refer: ignoreTextChanged

you can use EntryRenderer to detect keypress event and use that flag to detect the change by code or by UI.
Here are the step:
- Exetend your entry control with new event OnTextChangeByUI
- Write custom render for both platform
e.g for android it will be something like this
public class ExtendedEntryRender : EntryRenderer
{
protected override void OnElementPropertyChanged(object sender, PropertyChangedEventArgs e)
{
base.OnElementPropertyChanged(sender, e);
if (Control != null)
{
Control.KeyPress += ((Entry)Element).OnTextChangeByUI;
}
}
}

C# richBox1 text disable

I have problem with richBox1 text disabling.
I've tryed richTextBox1.readonly = true; and richTextBox1.Enabled = false;
My code:
private void richTextBox1_TextChanged(object sender, EventArgs e)
{
richTextBox1.ReadOnly = !richTextBox1.ReadOnly;
}
Its disabling after one letter.
EDIT: And if disable I can still copy text but cant write there.

Honestly, disabling expected functionality is not something you should be doing. It is not good UI design.

The event TextChanged is fired every time the text changes (including writing or removing one letter). You can use Form's Load event (by double clicking the form on design time) :
private void Form1_Load(object sender, EventArgs e)
{
richTextBox1.ReadOnly = true;
richTextBox1.Enabled = false;
}

How to get ListBox to load after selecting ComboBox value?

Working in VS 2012, WinForms, C#...
I have a ListBox I would like to populate depending upon the value selected in a ComboBox. I've tested my SQL Query and it works, but I'm getting a weird problem where, when I run my routines, my ComboBox comes up empty, as well as my ListBox. When I comment out the code in my cb_Session_SelectedValueChanged routine, my CB and LB load just fine, but when it's not commented out is when my LB and CB end up blank.
This is what I have:
private void cb_Session_SelectedValueChanged(object sender, EventArgs e)
{
listbox_Sessions.Visible = true;
LoadSessionListbox();
}
private void LoadSessionListbox()
{
int tempID = Convert.ToInt32(cb_Session.SelectedValue);
// Code here to load listbox, which works without above routine.
}
Am I missing something? Why are my CB and LB blank with that first routine added?
[EDIT]:
I put the routines which were in SelectedValueChanged in a MouseClick event and it works, but not when I want it to... You have to click a couple times to get it to re-load with the correct ID. I feel like I'm getting closer, but still not the right event.

Try this:
private void cb_Session_SelectedValueChanged(object sender, EventArgs e)
{
if(cb_Session.SelectedValue>-1)
{
listbox_Sessions.Visible = true;
LoadSessionListbox();
}
}

Figured it out!!
I ended up adding a simple if statement to my SelectedValueChanged routine, and it fixed everything!
private void cb_Sessions_SelectedValueChanged(object sender, EventArgs e)
{
listBox_Sessions.Visible = true;
if (cb_Sessions.SelectedValue != null)
LoadSessionListbox();
}
Works perfectly now.

Try in SelectedIndexChanged Event and follow
private void cb_Session_SelectedIndexChanged(object sender, EventArgs e)
{
if (cb_Session.SelectedValue == null) return;
if (cb_Session.SelectedIndex == -1) return;
listbox_Sessions.Visible = true;
LoadSessionListbox((int)cb_Session.SelectedValue);
}
private void LoadSessionListbox(int selectedValue)
{
//TODO: Do stuff
}

Validate a textbox in a windows form

Windows form application(.Net 3.5) I have a textbox and a button on the form.
I want to disable the button once the textbox is empty.
I don't want to use this method. Because the button is still enabled.
Thanks.

In the event handler for TextChanged, simply determine if the text box contains any data. If it does, enable it. Otherwise, disable it. Add your event handler and then implement something like the following,
private void textBox1_TextChanged(object sender, EventArgs e)
{
button1.Enabled = !(textBox1.Text == String.Empty);
}

Handle the on text change event
check and see what textbox.text is like this
if(string.IsNullOrEmpty(textbox1.text))
{
Button1.enabled = false;
}

if you want to disable the textbox, then using textChanged:
if (textbox.Text == ""){
button.Enabled = false;
}
Hope it helps

Make button1.Enabled = false;
and add EventHandler to textbox1.TextChanged = new System.EventHandler(SearchBoxTextChanged);
private void textbox1_TextChanged(object sender, EventArgs e)
{
button1.Enabled = (textBox1.Text.Trim() != string.Empty);
}

How can I make an event for getting focus for double click on textbox? (Windows Phone)

I have a textBox and I call an event get focus, when click on it. The behaviour is different when I make a double click on it, how can I make an event for getting focus for double click on this textbox?

You can use the OnTap() and OnDoubleTap() methods of the TextBox. And in each method you can define the different logic and set the focus on the TextBox.
Update:
Here's a simple code structure on how to make it work:
XAML:
<TextBox x:Name="InputTextBox" Margin="0,0,0,520" />
C#
public MainPage()
{
InitializeComponent();
InputTextBox.Tap += InputTextBoxTap;
InputTextBox.DoubleTap += InputTextBoxDoubleTap;
}
private void InputTextBoxDoubleTap(object sender, System.Windows.Input.GestureEventArgs e)
{
InputTextBox.Text = "Double tapped!";
}
private void InputTextBoxTap(object sender, System.Windows.Input.GestureEventArgs e)
{
InputTextBox.Text = "Tapped!";
}
I tested this on both the emulator and on a device and it works in both cases!

The reason is simple.
If you have notice the arguments supplied are different
private void textBox1_MouseDoubleClick(object sender, MouseEventArgs e)
{
}
private void textBox1_Click(object sender, EventArgs e)
{
}
Yes if you want them to resemble the same you can select "MouseClick" event from the properties.
Cheers!