I need to check if the RadioButton is checked from the checkchanged event
private void radioButton6_CheckedChanged_2(object sender, EventArgs e)
{
if(radioButton6.Checked)
{
}
}
Is this the properway to do it? Can i access the CheckBox state from the sender object?
Is this the properway to do it?
That depends. If you need each radio button to be very much distinguished. Meaning: You really need to check inside the event method:
if(radioButton6.Checked)
Then this is the way to go. Another case where this can be applied is when you have registered an individual event handler for each radio button. Then you can access the button directly, because in this case the sender will always be e.g. radioButton6.
Can i access the CheckBox state from the sender object?
Yes you can. It might be adviseable in this case: If you decide to register the same method to a bunch of different radio button events then you could use the sender and cast it. This might save you a lot of double code.
private void radioButton6_CheckedChanged_2(object sender, EventArgs e)
{
RadioButton button = sender as RadioButton;
if(button?.Checked == true)
{
}
}
In such a case you can use the Tag property of the RadioButton to distinguish them. Set it in the beginning and then you can check for it.
Related
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);
}
}
In my Windows forms application written in C# I have a bunch of buttons. When the user's mouse hovers over a button, I want the button's border to change.
Currently I have multiple instances of the following (a copy for each button):
private void btnStopServer_MouseEnter(object sender, EventArgs e)
{
oldColor = btnStopServer.FlatAppearance.BorderColor;
btnStopServer.FlatAppearance.BorderColor = mouseOverColor;
}
private void btnStopServer_MouseLeave(object sender, EventArgs e)
{
btnStopServer.FlatAppearance.BorderColor = oldColor;
}
Since I have a lot of buttons, the code to change the color of the button's border takes up a lot of space.
Is there any simpler way that I could do this?
You should wire-up a single MouseEnter and MouseLeave to each control that needs this functionality (rather than writing a new version of each method for each control). Assuming you're using Visual Studio, this can be done by changing the target method name for the event, in each Button's property pane. If you write the following code first, then this method will appear in the property's MouseEnter and MouseLeave events' drop-down lists.
The code would then need to check which button from which the event was fired, as follows:
private void btnWithHoverBorder_MouseEnter(object sender, EventArgs e)
{
Button eventButton = (Button) sender;
oldColor = eventButton.FlatAppearance.BorderColor;
eventButton.FlatAppearance.BorderColor = mouseOverColor;
}
private void btnWithHoverBorder_MouseLeave(object sender, EventArgs e)
{
Button eventButton = (Button) sender;
eventButton.FlatAppearance.BorderColor = oldColor;
}
I presume oldColor is a global? This might get out of sync if something "odd" happens where your MouseEnter event is fired for another button, before the corresponding MouseLeave is caught. To make this more robust, I'd consider storing the old color on the Button's .tag property, so that it's self-contained.
Eg:
private void btnWithHoverBorder_MouseEnter(object sender, EventArgs e)
{
Button eventButton = (Button) sender;
eventButton.tag = eventButton.FlatAppearance.BorderColor;
eventButton.FlatAppearance.BorderColor = mouseOverColor;
}
private void btnWithHoverBorder_MouseLeave(object sender, EventArgs e)
{
Button eventButton = (Button) sender;
eventButton.FlatAppearance.BorderColor = (Color)eventButton.tag;
}
(The tag is basically a hook on which to tag "anything" relevant to a specific instance of a control, that there is not already a property for. It's of type Object which means you can tag anything there, but when you read from it, you need to cast it back to whatever type you put there in the first place. But because it's an Object you can put anything there, including eg a custom class that contains multiple properties, or an array, etc if you need to tag a control with more than one thing).
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;
...
Please read my question its not a duplicate one.
I've three radio buttons on windows form and all these buttons have common 'CheckedChanged' event associated. When I click any of these radio buttons, it triggers the 'CheckedChanged' event twice.
Here is my code:
private void radioButtons_CheckedChanged(object sender, EventArgs e)
{
//My Code
}
I inserted the breakpoint and the whole code within this event iterates twice.
Please tell me why it is behaving like this?
As the other answerers rightly say, the event is fired twice because whenever one RadioButton within a group is checked another will be unchecked - therefore the checked changed event will fire twice.
To only do any work within this event for the RadioButton which has just been selected you can look at the sender object, doing something like this:
void radioButtons_CheckedChanged(object sender, EventArgs e)
{
RadioButton rb = sender as RadioButton;
if (rb != null)
{
if (rb.Checked)
{
// Only one radio button will be checked
Console.WriteLine("Changed: " + rb.Name);
}
}
}
To avoid it, just check if radioButton is checked
for example:
private void radioButton1_CheckedChanged(object sender, EventArgs e)
{
if (radioButton1.Checked)
//your code
}
CheckedChanged is raised whenever the Checked property changes. If you select a RadioButton then the previously selected RadioButton is unchecked (fired CheckedChanged), and then the new RadioButton is checked (fired CheckedChanged).
It's triggering once for the radio button transition from checked to unchecked, and again for the radio button transitioning from unchecked to checked (i.e. any change in checked state triggers the event)
You could set the AutoCheck property true for each RadioButton then catch the Click event instead of the CheckChanged event. This would ensure that only one event is fired, and the logic in the handler can cast the sender to type RadioButton if needed to process the click. Often the cast can be avoided if the handler logic is simple. Here is an example which handles three controls, rbTextNumeric, rbTextFixed and rbTextFromFile:
private void rbText_Click(object sender, EventArgs e)
{
flowLayoutPanelTextNumeric.Enabled = rbTextNumeric.Checked;
txtBoxTextFixed.Enabled = rbTextFixed.Checked;
flowLayoutPanelTextFromFile.Enabled = rbTextFromFile.Checked;
}
{
public partial class Form3 : Form
{
public Form3()
{
InitializeComponent();
}
int click = 0;
private void radioButton1_Click(object sender, EventArgs e)
{
click++;
if (click %2==1)
{
radioButton1.Checked = true;
}
if (click %2==0)
{
radioButton1.Checked = false;
}
if (radioButton1.Checked==true)
{
label1.Text = "Cheked";
}
if (radioButton1.Checked==false)
{
label1.Text = "Uncheked";
}
}
}
}
The other answers are correct but miss the reason for the underlying problem.
When a radio button is checked the first event sent is the change from the unchecked item
however if you check its state by its control name you will still see its old checked status because the form has not been updated yet. To see its true status you need to cast the sender object.
This allows you to perform any actions relating to the condition which is being deselected should you need to do so.
In the not uncommon scenario below multiple radio buttons are sent to the same handler event.
Simply checking the state of the sender for checked will not work here as we need to perform different actions depending on which radio button has been pressed.
So first we ignore any sender that has just been unchecked.
then we identify the checked sender by control name to process the correct action.
private void ModeChangedExample(object sender, EventArgs e)
{
// multiple radio buttons come here
// We only want to process the checked item.
// if you need to something based on the item which was just unchecked don't use this technique.
// The state of the sender has not been updated yet in the form.
// so checking against rdo_A check state will still show it as checked even if it has just been unchecked
// only the sender variable is up to date at this point.
// To prevent processing the item which has just been uncheked
RadioButton RD = sender as RadioButton;
if (RD.Checked == false) return;
if (rdo_A.Name == RD.Name)
{
//Do stuff
}
if (rdo_B..Name == RD.Name)
{
// Do other stuff
}
if (rdo_C.Name == RD.Name)
{
// Do something else
}
}
This problem of double checking happens when there is a series of RadioButton Clicks in succession.I had this same problem.The last click will give two results.To overcome this i made a dummy click in the end.The double click stopped.Try this method.
Venkatraman
I have a tree view on the left side. Selecting a node displays relevant information in a form on the right side.
Would I be able to keep the tree and any one control (textbox, combobox, checkbox) on the right in focus at the same time? This will enable a user to select a field, make a change, select another node, and without having to go back and select the same field again, just type and change the value of the same field.
Thanx.
EDIT
I suppose one could implement such behaviour manually:
private Control __cFocus;
private void {anyControl}_Focus(object sender, EventArgs e)
{
__cFocus = (Control)sender;
}
private void treeView1_AfterSelect(object sender, EventArgs e)
{
__cFocus.Focus();
}
I was just wondering if there exists an automatic / more elegant solution
EDIT 2
Ok, so it seems I'll have to implement it manually. Manual implementation it is then. However, now there seem to be another problem; not sure if I should ask this as a separate question.
When selecting a node the textbox gains focus as intended, but only when using the keyboard. It doesn't work when selecting a node with the mouse. First I thought that it might be a mouse event that's interfering, but stepping revealed that the MouseUp event fired first and then the AfterSelect event which sets the focus, so I don't think it's interfering. The textbox's Enter event is also fired, but for some reason it loses focus again to the tree.
Thanx
no, you cannot keep two controls in focus at the same time. But what you can do is set the focus to the target control in the treeview AfterSelect event
private void treeView1_AfterSelect(object sender, TreeViewEventArgs e)
{
textBox1.Focus();
textBox1.SelectAll();
}
then in your textbox leave, save the changes, like so:
private void textBox1_Leave(object sender, EventArgs e)
{
//save changes here
}
this way, everytime you select an item in the treeview, check your textbox for change and save as needed, then you will refocus on the textbox for your next edit
There only can be one element having the focus!
But I have an idea for you that might solve your problem. Assuming you have a window with a TreeView and a TextBox. Set the HideSelection property of the TreeView to false and subscribe the AfterSelect event (like edeperson already answered) like this:
private void OnTreeViewAfterSelect(object sender, TreeViewEventArgs e)
{
textBox1.Text = e.Node.Text;
textBox1.Focus();
}
Then subscribe the KeyDown event of the TextBox and do following in the event method:
private void OnTextBoxKeyDown(object sender, KeyEventArgs e)
{
if ((e.KeyCode == Keys.Up) || (e.KeyCode == Keys.Down))
{
treeView1.Focus();
SendKeys.Send(e.KeyCode == Keys.Up ? "{UP}" : "{DOWN}");
}
}
At last subscribe the Leave event of the TextBox and do following in the event method:
private void OnTextBoxLeave(object sender, EventArgs e)
{
if (treeView1.SelectedNode != null)
{
treeView1.SelectedNode.Text = textBox1.Text;
}
}
And, voilá it should work like you expected it...
If you want to focus on it , you can use usercontrol. you can put your textbox on usercontrol and set focus of this textbox on usercontrol using set properties on treeview select.
No you may not, only one control may be in focus at any given time.
See Moonlight's comment for one way to achieve the behavior that you seek.