I copied this code from the other question. It should work, but it failed in my try. Can any one tell me why? thanks!
private void Form1_Load(object sender, EventArgs e)
{
textBox1.DataBindings.Add("Text", this, "Unit");
}
private int unit;
public event EventHandler UnitChanged; // or via the "Events" list
public int Unit
{
get { return unit; }
set
{
if (value != unit)
{
unit = value;
EventHandler handler = UnitChanged;
if (handler != null) handler(this, EventArgs.Empty);
}
}
}
private void button1_Click(object sender, EventArgs e)
{
Unit++;
}
You're incrementing the private field (lowercase unit), rather than the property bound to the TextBox (uppercase Unit).
Try changing the code here:
private void button1_Click(object sender, EventArgs e)
{
Unit++;
}
Related
I created a usercontrol that contains many buttons and in the main form I have a textbox.
I add the usercontrol to the main form and I want to click any button on the usercontrol and have the textbox in the main form shows the button text.
The question is how to pass the string of the button in usercontrol to the textbox in the main form? This is what I'm trying to do
public partial class UserControl1 : UserControl
{
public UserControl1()
{
InitializeComponent();
}
public string a ;
private void button1_Click(object sender, EventArgs e)
{
a = button1.Text;
}
private void button2_Click(object sender, EventArgs e)
{
a = button2.Text;
}
private void button3_Click(object sender, EventArgs e)
{
a = button3.Text;
}
and the main form code is :
private void textBox1_TextChanged(object sender, EventArgs e)
{
textBox1.Text = usrCtrl.a;
// usrCtrl come from : Usercontrol1 usrCtrl = new Usercontrol1();
}
and it shows nothing in the textbox.
refer to this answer, you need to create a property changed event.
UserControl.cs class;
public partial class UserControl1 : UserControl
{
public event PropertyChangedEventHandler PropertyChanged;
public UserControl1()
{
InitializeComponent();
}
private string stringA;
public string a
{
get { return stringA; }
set
{
if (value != stringA)
{
stringA = value;
if (PropertyChanged!= null)
{
PropertyChanged(this, new PropertyChangedEventArgs(a));
}
}
}
}
private void button1_Click(object sender, EventArgs e)
{
a = button1.Text;
}
private void button2_Click(object sender, EventArgs e)
{
a = button2.Text;
}
private void button3_Click(object sender, EventArgs e)
{
a = button3.Text;
}
private void button4_Click(object sender, EventArgs e)
{
a = button4.Text;
}
}
On Form's Load we need to define the event,
private void Form1_Load(object sender, EventArgs e)
{
cntr.PropertyChanged += Cntr_PropertyChanged; // press tab + tab after += and it will generate the following method automatically.
}
Here is Event;
private void Cntr_PropertyChanged(object sender, PropertyChangedEventArgs e)
{
textBox1.Text = cntr.a.ToString(); //cntr is the instance of UserControl1
}
Hope helps,
Your code to change the textBox1.Text value is in the wrong event handler.
The textBox1_TextChanged event handler only fires when text in that field changes.
What you need to do is put the line:
textBox1.Text = a;
in the click event handlers.
I am trying to return a value when a grid cell has been double clicked. Here is my code for setting up my delegate and event handler:
public class SelectedItemEventArgs : EventArgs
{
public string SelectedChoice { get; set; }
}
public event EventHandler<SelectedItemEventArgs> ItemHasBeenSelected;
Here is my code for setting up the double click:
private void dataGridView1_CellDoubleClick(object sender, DataGridViewCellEventArgs e)
{
var handler = ItemHasBeenSelected;
if (handler != null)
{
handler(this, new SelectedItemEventArgs
{ SelectedChoice = txtCustomer.Text.ToString() });
}
}
Handler is always null. If I change the event handler code to this:
private void dataGridView1_CellDoubleClick(object sender, DataGridViewCellEventArgs e)
{
var handler = ItemHasBeenSelected;
string choice = dataGridView1[0, e.RowIndex].ToString();
if (choice != null)
{
handler(this, new SelectedItemEventArgs
{ SelectedChoice = choice});
}
}
I get the error "Object reference not set to an instance of an object." I did see this: C# Delegate returns back NULL but I couldn't figure out how it worked. I ultimately want the value of dataGridView1[0, e.RowIndex] returned.
You have to ensure method is added into event before calling event.
private void Form1_Load(object sender, EventArgs e)
{
ItemHasBeenSelected += Form1_ItemHasBeenSelected;
}
private void Form1_ItemHasBeenSelected(object sender, SelectedItemEventArgs e)
{
MessageBox.Show("Chosen: " + e.SelectedChoice);
}
However, event is in fact for loosely coupling.
If everything is under your control, just directly call a method and save yourself from events.
Here is my code in my userControl
public partial class UserControlHomeScreen : UserControl
{
public event EventHandler SomethingHappened;
public void DoSomething()
{
EventHandler handler = SomethingHappened;
if (handler != null)
{
handler(this, EventArgs.Empty);
}
}
public void HandleEvent(object sender, EventArgs args)
{
MessageBox.Show("Wafak.");
}
public UserControlHomeScreen()
{
InitializeComponent();
}
private void btnAverageDailyBal_Click(object sender, EventArgs e)
{
this.Tag = 0;
this.Hide();
}
private void btnComputeTransferPricing_Click(object sender, EventArgs e)
{
this.Tag = 1;
this.Hide();
}
}
And here is my code in my main form
private void HomeScreen()
{
uHomeScreen = new UserControlHomeScreen();
uHomeScreen.Dock = DockStyle.Fill;
//uHomeScreen.Disposed += new EventHandler(uHomeScreen_Disposed);
uHomeScreen.SomethingHappened += new EventHandler(uHomeScreen_SomethingHappened);
panelMain.Controls.Add(uHomeScreen);
}
void uHomeScreen_SomethingHappened(object sender, EventArgs e)
{
MessageBox.Show("throw new NotImplementedException();");
}
What i want to happen is that when the usercontrol is hidden i want to fire an event in my main form but does not work, what am i missing? please help. thanks!
Your naming convention for event raiser (DoSomething) is confusing, your code doesn't call DoSomething (or raise the event SomethingHappened), so how could it fire for you? Add the following code in your user control class:
//override the OnVisibleChanged
protected override void OnVisibleChanged(EventArgs e){
if(!Visible) DoSomething();
}
i created user control which looks like this:
and code behind looks like:
using System;
using System.Windows.Forms;
namespace Controlls
{
public partial class Toolbar : UserControl
{
public Toolbar()
{
InitializeComponent();
}
private void pbNaprej_Click(object sender, EventArgs e)
{
}
private void pbNazaj_Click(object sender, EventArgs e)
{
}
private void pbNovo_Click(object sender, EventArgs e)
{
}
private void bpbBrisi_Click(object sender, EventArgs e)
{
}
private void pbPotrdi_Click(object sender, EventArgs e)
{
}
private void txtOd_TextChanged(object sender, EventArgs e)
{
}
}
}
now i move this UC to form but there is a problem. How to get this events from UC. I need to implement click events for buttons in form where i use this user control. What i can see is that i can use it like one component and i can not get separate buttons from it.
Add 2 event handlers for yor control, and subscribe to the toobox event at the place you use it:
using System;
using System.Windows.Forms;
namespace Controlls
{
public enum ToolboxButtonType { Potrdi, Brisi, Novo, Nazaj, Naprej }
public partial class Toolbar : UserControl
{
public Toolbar()
{
InitializeComponent();
}
private void pbNaprej_Click(object sender, EventArgs e)
{
OnToolboxClick(ToolboxButtonType.Naprej);
}
private void pbNazaj_Click(object sender, EventArgs e)
{
OnToolboxClick(ToolboxButtonType.Nazaj);
}
private void pbNovo_Click(object sender, EventArgs e)
{
OnToolboxClick(ToolboxButtonType.Novo);
}
private void bpbBrisi_Click(object sender, EventArgs e)
{
OnToolboxClick(ToolboxButtonType.Brisi);
}
private void pbPotrdi_Click(object sender, EventArgs e)
{
OnToolboxClick(ToolboxButtonType.Potrdi);
}
private void txtOd_TextChanged(object sender, EventArgs e)
{
OnTextChanged(txtOd.Text);
}
}
private OnToolboxClick(ToolboxButtonType button)
{
if (ToolboxClick != null)
{
ToolboxClick(this, new ToolboxClickEventArgs(button));
}
}
private OnTextChanged(string text)
{
if (ToolboxTextChanged!= null)
{
ToolboxTextChanged(this, new ToolboxTextChangedEventArgs(text));
}
}
public class ToolboxTextChangedEventArgs: EventArgs
{
public string Text { get; private set; }
public ToolboxClickEventArgs(string text) { Text = text; }
}
public class ToolboxClickEventArgs : EventArgs
{
public ToolboxButtonType Button { get; private set; }
public ToolboxClickEventArgs(ToolboxButtonType button) { Button = button; }
}
public event EventHandler<ToolboxClickEventArgs> ToolboxClick;
public event EventHandler<ToolboxTextChangedEventArgs> ToolboxTextChanged;
}
For example:
//Toolbar toolbar = new Toolbar();
toolbar.ToolboxTextChanged += (s, e) => { btn1.Text = e.Text; };
toolbar.ToolboxClick += (s, e) =>
{
swith(e.Button)
{
case ToolboxButtonType.Brisi: //
break;
default:
break;
}
};
You need to create event in MainForm class and generarate it in hand mode.
If you also draw your icons on canvas or smth, you need to handle onClick your MainForm, than calculate mouse click position, and generate event that you were create.
If it amount of buttons or smth that has their own onClick events, you can hang on this buttons event the action that will generate your even in main form.
Answer what approach you use, and I past some code.
ADDED:
public partial class Toolbar : UserControl
{
public Toolbar()
{
InitializeComponent();
}
public enum ToolBarCommands
{
Naprej, Nazaj, Novo
}
public Action<object, ToolBarCommands> MenuItemClick;
private void pbNaprej_Click(object sender, EventArgs e)
{
if(MenuItemClick != null)
MenuItemClick(this, ToolBarCommands.Naprej);
}
private void pbNazaj_Click(object sender, EventArgs e)
{
if(MenuItemClick != null)
MenuItemClick(this, ToolBarCommands.Nazaj);
}
private void pbNovo_Click(object sender, EventArgs e)
{
if(MenuItemClick != null)
MenuItemClick(this, ToolBarCommands.Novo);
}
}
How to use it? easy:
// Define section
var toolbar = new Toolbar();
toolbar.MenuItemClick += MenuItemClickHandler;
...
MenuItemClickHandler(object sender, Toolbar.ToolBarCommands item)
{
switch(item)
{
case Toolbar.ToolBarCommands.Naprej:
// Naperej handler
break;
case Toolbar.ToolBarCommands.Nazaj:
// Nazaj handler
break;
case Toolbar.ToolBarCommands.Novo:
// Novo handler
break;
}
}
ADDED:
If names of your buttons same as enum members you can cut this part of code:
private void pbNaprej_Click(object sender, EventArgs e)
{
if(MenuItemClick != null)
MenuItemClick(this, ToolBarCommands.Naprej);
}
private void pbNazaj_Click(object sender, EventArgs e)
{
if(MenuItemClick != null)
MenuItemClick(this, ToolBarCommands.Nazaj);
}
private void pbNovo_Click(object sender, EventArgs e)
{
if(MenuItemClick != null)
MenuItemClick(this, ToolBarCommands.Novo);
}
It will look's like one method (hang this method to all your menu element events)
private void pbItem_Click(object sender, EventArgs e)
{
if(MenuItemClick != null)
{
ToolBarCommands command;
var res = ToolBarCommands.TryParse(((Button)sender).Name, command)
if(res == true)
MenuItemClick(this, command);
}
}
I'm sync my data from Grid to DataBase using really weird way :
for example :
#region Line methods
private void LinesView_UserDeletedRow(object sender, DataGridViewRowEventArgs e)
{
lineTableAdapter.Update(fRIIBDataSet.Line);
}
private void LinesView_CellValueChanged(object sender, DataGridViewCellEventArgs e)
{
lineTableAdapter.Update(fRIIBDataSet.Line);
}
private void LinesView_RowValidated(object sender, DataGridViewCellEventArgs e)
{
lineTableAdapter.Update(fRIIBDataSet.Line);
}
#endregion
but when I switched some columns to ComboBox I need to make some trick before Update alike that :
private void dataGridView1_RowValidated(object sender, DataGridViewCellEventArgs e)
{
//deltaTableAdapter.Update(fRIIBDataSet.Delta); TODO
}
private void dataGridView1_UserDeletedRow(object sender, DataGridViewRowEventArgs e)
{
deltaTableAdapter.Update(fRIIBDataSet.Delta);
}
private void dataGridView1_CellValueChanged(object sender, DataGridViewCellEventArgs e)
{
if (lambdacat != null)
{
string selected = (LimView.Rows[e.RowIndex].Cells[1] as DataGridViewComboBoxCell).FormattedValue.ToString();
if (selected != "")
{
int find = Array.IndexOf(dict, dict.Where(x => x == selected).FirstOrDefault());
LimView.Rows[e.RowIndex].Cells[0].Value = dictiddarray[find];
//deltaTableAdapter.Update(fRIIBDataSet.Delta);
}
}
//deltaTableAdapter.Update(fRIIBDataSet.Delta);
}
troubles comes after uncommenting Update method.
When I opening the window with a table I've got error message : Damaged the internal index DataTable: "5. " How can I fix / avoid this error ?
Does modifying it to this work ?
if (selected != "")
{
int find = Array.IndexOf(dict, dict.Where(x => x == selected).FirstOrDefault());
LimView.Rows[e.RowIndex].Cells[0].Value = dictiddarray[find];
fRIIBDataSet.Delta.BeginInit(); //
deltaTableAdapter.Update(fRIIBDataSet.Delta);
fRIIBDataSet.Delta.EndInit();
}