I'm using c# and I have a MenuStrip control but I don't know how to identify what item of it is being clicked. For example, I used to group all click(buttons) events in one or two methods like "btnActions_click()" or "btnNavigation_click()". Then, inside of the method I identify the button clicked by parsing the sender as a button and placing it on a button var, then I check if the name of that button var is equal to "btnFoo" or "btnBar".
So, in this case, how could I know what item of the MenuStrip controls is being clicked in order to group all click events in only one method?
I apologyze if my english isn't correct. If you can't understand me I can try again or post some code.
Thanks.
Edit: I didn't post any code because I thought that there was not necessary in this question but someone suggest me to do it, so I'll do it. Here's an example of what I do to identify what button has been clicked.
private void btnNavegation_Click(object sender, EventArgs e)
{
Button btn = sender as Button;
if (btn.Name == "btnNext")
//go to next item of the list
else if (btn.Name == "btnPrevious")
//go to previous item of the list
}
I think that you need to subscribe to ItemClicked event (inherited from ToolStrip), instead of subscribing to Click event (inherited from Control).
The example provided by Microsoft's documentation show you how to determine the clicked item on each call (ToolStripItemClickedEventArgs::ClickedItem):
private void ToolStrip1_ItemClicked(Object sender, ToolStripItemClickedEventArgs e)
{
System.Text.StringBuilder messageBoxCS = new System.Text.StringBuilder();
messageBoxCS.AppendFormat("{0} = {1}", "ClickedItem", e.ClickedItem );
messageBoxCS.AppendLine();
MessageBox.Show(messageBoxCS.ToString(), "ItemClicked Event" );
}
Related
I have a windows form application with multiple buttons. I need to retrieve the text property of any button clicked in order to create a query to the database. the only way I know is to create a button click event and cast the sender as button then do a switch case for each button Id which seems very hectic since I probably will have more than 100 buttons in the entire application. So my question is there a generic key press method I can create which can retrieve the text property of any button pressed/clicked on the form? Please excuse me if the question is not very clear. Any help will be appreciate
Use a single click event handler for all similar kind of buttons. This way there will be click event subscribed for every button but only one method which will be executed for all buttons. You can determine which button was pressed as follows.
Using sender object as follows;
private void button_Click(object sender, EventArgs e)
{
var buttonText = ((Button)sender).Text;
//Query using buttonText
}
Update:
Above answer will still require you to subscribe click event for each button. If you don't want that then have a look at following approach;
You could use (ClickTransparentButton or) disable (Enabled=false) all these buttons and add click event on parent Form. Once you get click event you can get button which was clicked as follows;
private void Form1_Click(object sender, EventArgs e)
{
var p = PointToClient(Cursor.Position);
var control = GetChildAtPoint(p);
if(control is Button)
{
var buttonText = ((Button)control).Text;
//Query using buttonText
}
}
But this has few disadvantages such as, you will not be able to operate these buttons using keyboard.
and more...
Create some function as buttons click handler:
private void buttonClickHandler(object sender, EventArgs e)
{
string buttonName = (sender as Button).Text;
}
2A. Connect Click event of every button to this handler.
2B. To automate connection of button click handler use something like that:
private void connectButtonsHandlers()
{
foreach(var c in this.Controls)
{
if(c is Button)
{
(c as Button).Click += buttonClickHandler;
}
}
}
Add this code to form constructor to perform connection at program start.
I have 10 buttons, 0-9 (button0, button1, button2...). When I click any of these buttons, I would like to perform the same routine on them. I would like to know how to, upon clicking of any of these buttons, direct them to the routine below.
private void button0_Click(object sender, EventArgs e)
{
int newValue;
newValue = Convert.ToInt32(Button.text);
}
I have already gone into the properties of each button, then events, and changed the click event to button0_Click (I would have thought this would add "handles button1.click, button2.click, etc." after "private void button0_Click(object sender, EventArgs e)" but if it does that in the background, that's ok as long as it works.)
I also need to know how to identify the button that has been pressed, which is where I'm at with "Convert.ToInt32(Button.text)" (e.g. button2.text = "2").
You can select the same event handler for all the buttons in the designer (in the event tab of the properties window, select the event and there'll be a drop down with all your defined event handlers).
To get which button has been clicked on, cast the sender argument to a Button and you'll have it.
Button button = (Button)sender;
int value = int.Parse( button.Text );
Edit: Also, the "Handles control.event" syntax only exists in Visual Basic.
Edit: Check out the generated code (Form1.Designer.cs, for example) to see how the events are hooked up.
The C# language doesn't use handles to bind events (as VB does). The code for the actual binding is in the generated code for the form, i.e. in the background as you put it.
The sender property is a reference to the control where the event happened. You just need to cast it to the actual type of the control:
private void button0_Click(object sender, EventArgs e)
{
Button button = (Button)sender;
int newValue = Convert.ToInt32(button.text);
}
As an alternative to using the text of the button (for example if you want to translate the application to different languages, or simply don't want to rely on the text), you can put whatever you like in the Tag property of each button, and retrieve it in the event handler.
You could wire them all up to the same event handler an extract the button from sender e.g.
private void button0_Click(object sender, EventArgs e)
{
var button = sender as Button
if (button != null)
{
int newValue = Convert.ToInt32(Button.text);
}
}
I have a Windows form named Form1 and panel within this form named panel1. I use the panel only to place buttons there so that I can group them and work with them separately from the other buttons in my Form1. For the purpose of my program I need to handle every button click made from the buttons inside panel1. For this purpose I use the same code snippet:
public Form1()
{
InitializeComponent();
// Set a click event handler for the button in the panel
foreach (var button in panel1.Controls.OfType<Button>())
{
button.Click += HandleClick;
}
}
What I need to do is to have a way to identify which button exactly has been clicked. For this purpose I played a little bit with my handler method:
private void HandleClick(object o, EventArgs e)
{
MessageBox.Show("HI" + o.ToString());
}
which gave me some hope because I get this:
It's the second part - Text: button4 which is actually enough information to continue with my work. But I can't find a way to get this piece of information without some complicated string manipulations. So is there a way to get this or other unique information about the button been clicked given the way I have written my code?
private void HandleClick(object sender, EventArgs e)
{
var btn = sender as Button;
if (btn != null)
{
MessageBox.Show(btn.Text);
}
}
One option is to cast the object to a Button, but rather than doing the casting you can change how the event handler is assigned so that you don't need to cast in the first place:
foreach (var button in panel1.Controls.OfType<Button>())
{
button.Click += (_,args)=> HandleClick(button, args);
}
Then just change the signature of HandleClick to:
private void HandleClick(Button button, EventArgs e);
You need to cast sender to the Button class so you can access its properties:
Button b = (Button)sender;
MessageBox.Show(b.Text);
I made a custom button that has a field named Data.
I add this button programatically during runtime to my winform and on adding I also define a click event for them. Well, Actually I only have one method and I subscribe the newly added buttons to this method.
But in the click event I want to access this Data field and show it as a message box, but it seems that my casting is not right:
CustomButton_Click(object sender, EventArgs e)
{
Button button;
if (sender is Button)
{
button = sender as Button;
}
//How to access "Data" field in the sender button?
//button.Data is not compiling!
}
UPDATE:
I am sorry, I ment with "is not compiling" that .Data does not show up in intelisense...
You need to cast to the type of your custom class that has the Data field.
Something like:
YourCustomButton button = sender as YourCustomButton;
Assuming your custom button type is CustomButton, you should do this instead:
CustomButton_Click(object sender, EventArgs e){
CustomButton button = sender as CustomButton;
if (button != null){
// Use your button here
}
}
If you dont want to set a variable the simple way to do is:
((CustomButton)sender).Click
or whatever you want.
I found a funny check assignment in a win forms project on Github:
private void btn_Click(object sender, EventArgs e){
// here it checks if sender is button and make the assignment, all in one shot.
// Bad readability, thus not recommended
if (!(sender is Button senderButton))
return;
var _text = senderButton.Text;
...
I currently determine what page of a tabcontrol was clicked on via the SelectedIndexChanged event.
I would like to detect before the selected index actually changes, for validation purposes. For example, a user clicks a tab page other than the one they are viewing. A dialog is presented if form data is unsaved and asks if it's ok to proceed. If the user clicks no, the user should remain on the current tab.
Currently I have to remember the previous tab page and switch back to it after an answer of 'no.'
I considered MouseDown (and the assorted calculation logic), but I doubt that's the best way.
Add such an event to the tabControl when form_load:
tabControl1.Selecting += new TabControlCancelEventHandler(tabControl1_Selecting);
void tabControl1_Selecting(object sender, TabControlCancelEventArgs e)
{
TabPage current = (sender as TabControl).SelectedTab;
// Validate the current page. To cancel the select, use:
e.Cancel = true;
}
I've actually tried all of the events including the suggestions here and none of the mentioned events occur at the right time to actually trap moving from the tab.
Even the tab page validation event fires when entering the tab rather than leaving it - either that or there's something peculiar going on with my machine or .NET 4. On the other hand, in .NET 4 there is the Deselecting event which fires at the right time for my purposes.
private void tab_Deselecting(object sender, TabControlCancelEventArgs e)
{
}
The TabControl has a collection of TabPages, each of which you can enforce validation on, e.g.:
public partial class MyForm : Form
{
public MyForm()
{
InitializeComponent();
foreach (var page in _tabControl.TabPages.Cast<TabPage>())
{
page.CausesValidation = true;
page.Validating += new CancelEventHandler(OnTabPageValidating);
}
}
void OnTabPageValidating(object sender, CancelEventArgs e)
{
TabPage page = sender as TabPage;
if (page == null)
return;
if (/* some validation fails */)
e.Cancel = true;
}
}