I have a Form with a LayoutPanel that has dynamically added buttons inside. The buttons are added at runtime, which works, but my problem is I'd like to set the properties to one of the buttons to disabled if a textBox is empty and enable it when it the textBox is not empty.
Here is a code example, with the error I am receiving below:
private void Form1_Load(object sender, EventArgs e)
{
// Create 3 buttons
Button button1 = new Button();
button1.Name = "button1";
tableLayoutPanel1.Controls.Add(button1, 0, 0);
Button button2 = new Button();
button1.Name = "button2";
tableLayoutPanel1.Controls.Add(button2, 0, 0);
Button button3 = new Button();
button3.Name = "button1";
tableLayoutPanel1.Controls.Add(button3, 0, 0);
}
private void textBox1_TextChanged(object sender, EventArgs e)
{
if (string.IsNullOrEmpty(textBox1.Text))
{
button1.Enabled = false;
}
else
{
button1.Enabled = true;
}
}
CS0103 The name 'button1' does not exist in the current context
Should I be declaring the buttons elsewhere so the entire code can see that they do in fact exist or is my problem elsewhere? Thanks.
You must declare a Button outside Form1_Load if you want to access the button with name directly from other methods, because in your case the buttons are just available in the Form1_Load method :
Button button1;
private void Form1_Load(object sender, EventArgs e)
{
// Create 3 buttons
button1 = new Button();
button1.Name = "button1";
tableLayoutPanel1.Controls.Add(button1, 0, 0);
}
private void textBox1_TextChanged(object sender, EventArgs e)
{
button1.Enabled = !string.IsNullOrEmpty(textBox1.Text);
}
or if you want declare Buttons inside Form1_Load, you can access to Button like this :
private void textBox1_TextChanged(object sender, EventArgs e)
{
var btn = tableLayoutPanel1.Controls.OfType<Button>().Where(x => x.Name == "button1").FirstOrDefault();
(btn as Button).Enabled = !string.IsNullOrEmpty(textBox1.Text);
}
As an alternative, you could dynamically get the control from the Layout Panel and set the enabled property like this:
private void textBox1_TextChanged(object sender, EventArgs e)
{
Control button = tableLayoutPanel1.Controls["button1"];
button.Enabled = string.IsNullOrEmpty(textBox1.Text) ? false : true;
}
This approach is not as "safe" as declaring the buttons at form level, but I thought it would be useful to mention for times when you need to be genuinely dynamic in referencing controls.
There are a couple ways you can do this, one would be to use the Find method of the TableLayoutPanel's Controls Collection like this.
private void textBox1_TextChanged(object sender, EventArgs e)
{
Button btn =(Button)tableLayoutPanel1.Controls.Find("button1", true)[0];
if (string.IsNullOrEmpty(textBox1.Text))
{
btn.Enabled = false;
}
else
{
btn.Enabled = true;
}
}
The second would be to use the buttons Tag Property to determine which control to use, I have used this in the past for dynamically generated controls.
private void Form1_Load(object sender, EventArgs e)
{
// Create 3 buttons
Button button1 = new Button();
button1.Name = "button1";
button1.Tag = 1; //note the Tag property being used
tableLayoutPanel1.Controls.Add(button1, 0, 0);
Button button2 = new Button();
button1.Name = "button2";
button2.Tag = 2;
tableLayoutPanel1.Controls.Add(button2, 0, 0);
Button button3 = new Button();
button3.Name = "button3";
button3.Tag = 3;
tableLayoutPanel1.Controls.Add(button3, 0, 0);
}
private void textBox1_TextChanged(object sender, EventArgs e)
{
foreach (Control c in tableLayoutPanel1.Controls) //iterate through controls
{
if ((int)c.Tag == 1) //if Tag is equal then process
{
if (c is Button)
{
if (string.IsNullOrEmpty(textBox1.Text))
{
((Button)c).Enabled = false;
}
else
{
((Button)c).Enabled = true;
}
break; //if you have multiple controls to process remove this
} //and assign the same tag to the controls you want processed
}
}
}
Related
I have created a function that creates a new panel each time a button is pressed, alongside with a button, which should remove the entire panel when pressed.
Here is my code for creating the panels and the button :
Panel panel;
private void button1_Click(object sender, EventArgs e)
{
panel = new Panel();
panel.BackColor = Color.FromArgb(38, 38, 38);
panel.Margin = new System.Windows.Forms.Padding(10);
flowLayoutPanel1.Controls.Add(panel);
panel.Show();
Button delbutton = new Button();
delbutton.Text = "X";
flowLayoutPanel1.Controls.Add(delbutton);
delbutton.Click += new EventHandler(this.ButtonFunction_Click);
}
Considering that every panel created has this delbutton , how can i remove the panel of which delbutton button was pressed?
I tried to add this method to the button, but it removes panel randomly :
void ButtonFunction_Click (Object sender,EventArgs e)
{
foreach (Control controlObj in flowLayoutPanel1.Controls)
{
flowLayoutPanel1.Controls.Remove(controlObj);
controlObj.Dispose();
}
}
You can add the relevant Panel as a Tag property of its Button, then you can get that in the Click handler
private void button1_Click(object sender, EventArgs e)
{
var panel = new Panel
{
BackColor = Color.FromArgb(38, 38, 38),
Margin = new Padding(10),
};
flowLayoutPanel1.Controls.Add(panel);
panel.Show();
var delbutton = new Button
{
Text = "X",
Tag = panel,
};
delbutton.Click += ButtonFunction_Click;
flowLayoutPanel1.Controls.Add(delbutton);
}
private void ButtonFunction_Click(Object sender, EventArgs e)
{
var button = (Button)sender;
((Control)button.Tag).Dispose();
button.Dispose();
}
I have a form, on which i placed 2 radio buttons. My issue is I need it to function in a way where if one is clicked, the other will be unclicked. I have the following code however it gets stuck in an inifinite loop once you do the first click and I do understand why. Wanted to see if any of you guys know how to go about making this in c#? I'm fairly new to c#
public partial class Form1 : Form
{
public Form1()
{
radAllCols.CheckedChanged += new EventHandler(this.radAllCols_Checked);
radSelCols.CheckedChanged += new EventHandler(this.radSelCols_Checked);
}
private void radAllCols_Checked(object sender, EventArgs e)
{
if (radAllCols.Checked == true)
{
radAllCols.Checked = false;
radSelCols.Checked = true;
}
}
private void radSelCols_Checked(object sender, EventArgs e)
{
if (radSelCols.Checked == true)
{
radSelCols.Checked = false;
radAllCols.Checked = true;
}
}
}
If the radio buttons have different RadioGroup values you have to first, unregister the Checked event, change the Checked property value and re-register the Checked event.
private void radAllCols_Checked(object sender, EventArgs e)
{
if (radAllCols.Checked == true)
{
radAllCols.CheckedChanged -= new
EventHandler(this.radAllCols_Checked);
radSelCols.CheckedChanged -= new
EventHandler(this.radSelCols_Checked);
radAllCols.Checked = false;
radSelCols.Checked = true;
radAllCols.CheckedChanged += new
EventHandler(this.radAllCols_Checked);
radSelCols.CheckedChanged += new
EventHandler(this.radSelCols_Checked);
}
}
private void radSelCols_Checked(object sender, EventArgs e)
{
if (radSelCols.Checked == true)
{
radAllCols.CheckedChanged -= new
EventHandler(this.radAllCols_Checked);
radSelCols.CheckedChanged -= new
EventHandler(this.radSelCols_Checked);
radSelCols.Checked = false;
radAllCols.Checked = true;
radAllCols.CheckedChanged += new
EventHandler(this.radAllCols_Checked);
radSelCols.CheckedChanged += new
EventHandler(this.radSelCols_Checked);
}
}
The code above is for very custom scenarios and should be avoided as much as possible. The radio boxes should behave the way you want automatically. Make sure you have the same RadioGroup property value on both of them.
RadioButtons placed in the same parent control (like a panel) behave this way by default.
There is no need to use a checked event for this.
Setting values of the radAllCols.Checked = true property fires the radAllCols_Checked event this causes your infinite "loop"
Since you are trying to uncheck the same radioButton to checked
private void radSelCols_Checked(object sender, EventArgs e)
{
if (radSelCols.Checked == true)
{
radSelCols.Checked = false; // reversed
radAllCols.Checked = true; // reversed
}
}
If you use GroupBox Container Element for same Radio Buttons that you want select one of them, you don`t need handle check state of Radio Buttons manually, When you select a Radio Button all the other Radio Buttons in the same group will be unchecked.
Your rest of the code is fine but you need to change your code in Checked methods() as mentioned below to prevent infinite loop and then it will work fine:
private void radAllCols_Checked(object sender, EventArgs e)
{
radAllCols.Checked = !radSelCols.Checked;
}
private void radSelCols_Checked(object sender, EventArgs e)
{
radSelCols.Checked = !radAllCols.Checked;
}
I have bunch of buttons on my form. And I would like to make it a bit nicer so button changing color and font to bold when mousei s over it seems like good idea. I would appreciate any help
button.BackColor = Color.Cyan;
button.Font = new Font(button.Font.Name, button.Font.Size, FontStyle.Bold);
EDIT:
this is working for me:
private void button1_MouseEnter(object sender, EventArgs e)
{
((Button)sender).BackColor = Color.PaleTurquoise;
((Button)sender).Font = new Font(((Button)sender).Font.Name, ((Button)sender).Font.Size, FontStyle.Bold);
}
private void button1_MouseLeave(object sender, EventArgs e)
{
((Button)sender).BackColor = Color.WhiteSmoke;
((Button)sender).Font = new Font(((Button)sender).Font.Name, ((Button)sender).Font.Size, FontStyle.Regular);
}
(there is button1_mousenter (or mouseleave) set as action for every button
Just select them all in your Form view and go to the mousehover event.
and write your code like this:
private void button_mousehover (object sender, EventArgs e)
{
((Button)sender).BackColor = Color.Cyan;
((Button)sender).Font = new Font(((Button)sender).Font.Name, ((Button)sender).Font.Size, ((Button)sender).FontStyle.Bold;
}
You can add MouseEnter and MouseLeave events to your buttons that changes the buttons' colors.
https://msdn.microsoft.com/en-us/library/system.windows.forms.control.mouseenter(v=vs.110).aspx
https://msdn.microsoft.com/en-us/library/system.windows.forms.control.mouseleave(v=vs.110).aspx
// bind handler to MouseEnter Event
this.yourButton1.MouseEnter += new System.EventHandler(this.allButtons_MouseEnter);
this.yourButton2.MouseEnter += new System.EventHandler(this.allButtons_MouseEnter);
// bind handler to MouseLeave Event
this.yourButton1.MouseLeave += new System.EventHandler(this.allButtons_MouseLeave);
this.yourButton2.MouseLeave += new System.EventHandler(this.allButtons_MouseLeave);
// enter handler
private void allButtons_MouseEnter(object sender, System.EventArgs e)
{
Button btn = (Button)sender;
btn.BackColor = Color.Cyan;
btn.Font = new Font(btn.Font.Name, btn.Font.Size, FontStyle.Bold);
}
// leave handler
private void allButtons_MouseLeave(object sender, System.EventArgs e)
{
Button btn = (Button)sender;
btn.BackColor = Color.DeepPink; // whatever your original color was
btn.Font = new Font(btn.Font.Name, btn.Font.Size, FontStyle.Regular);
}
I have array of buttons, and array of labels:
Label[] labels = new Label[10];
Button[] but = new Button[10];
While clicking the other button I want to dynamically create new button and new label from the array, i also want the but[i] to change the tex of labels[i]:
private void button1_Click(object sender, EventArgs e)
{
labels[i] = new Label();
labels[i].Location = new System.Drawing.Point(0, 15+a);
labels[i].Parent = panel1;
labels[i].Text = "Sample text";
labels[i].Size = new System.Drawing.Size(155, 51);
labels[i].BorderStyle = System.Windows.Forms.BorderStyle.FixedSingle;
a = labels[i].Height + labels[i].Top;
but[i] = new Button();
but[i].Text = "-";
but[i].Location = new System.Drawing.Point(0, labels[i].Height + labels[i].Top);
but[i].Parent = panel1;
but[i].Size = new System.Drawing.Size(155, 10);
but[i].Click += new System.EventHandler(but_Click);
i++;
}
private void but[i]_Click(object sender, EventArgs e)
{
labels[i].Text = "Changed Text";
}
But apparently I can't put an array in an event handler, how should I do it then?
One way to do this is to make your method return a handler instead of being a handler:
private EventHandler but_Click(int i)
{
return (s, e) => labels[i].Text = "Changed Text";
}
And use it like:
but[i].Click += but_Click(i);
Or do it inline:
but[i].Click += (s, ea) => labels[i].Text = "Changed Text";
What's happening in either of these is some compiler magic to capture the i variable. It's equivalent to this (which is also a valid, if verbose, way to do it):
class MyWrapper {
private int i;
public MyWrapper(int i) {
this.i = i;
}
public void TheHandler(object sender, EventArgs e) {
// TODO: capture the object that owns `labels` also, or this won't work.
labels[i].Text = "Changed Text";
}
}
//call with
but[i].Click += new EventHandler(new MyWrapper(i).TheHandler);
You could add the array index to the button as Tag property, and then pull it back out in but_Click.
So, add
but[i].Tag = i;
to the button creation. And then change the event handler:
private void but_Click(object sender, EventArgs e)
{
int buttonIndex = (int)((Button)sender).Tag;
labels[buttonIndex].Text = "Changed Text";
}
Or put the event handler inline:
but[i].Click += (s,e) => { label[i].Text = "Changed Text"; }
Or another option using the Tag property, add:
but[i].Tag = label[i];
...
private void but_Click(object sender, EventArgs e)
{
Label label = (Label)((Button)sender).Tag;
label.Text = "Changed Text";
}
Advantage of this approach is you're not relying on keeping arrays in synch after the initial creation of the controls.
I guess this is self-explaining:
public void SomeMehthod()
{
Button btn1 = new Button();
Button btn2 = new Button();
Button btn3 = new Button();
// Your button-array
Button[] btns = new Button[]
{
btn1,
btn2,
btn3
};
foreach(Button btn in btns)
{
// For each button setup the same method to fire on click
btn.Click += new EventHandler(ButtonClicked);
}
}
private void ButtonClicked(Object sender, EventArgs e)
{
// This will fire on any button from the array
// You can switch on the name, or location or anything else
switch((sender as Button).Name)
{
case "btn1":
// Do something
break;
case "btn2":
// Do something
break;
case "btn3":
// Do something
break;
}
}
Or if your array is accessible globaly:
Button[] btns = new Button[5];
Label[] lbls = new Label[5];
private void ButtonClicked(Object sender, EventArgs e)
{
Button clicked = sender as Button;
int indexOfButton = btns.ToList().IndexOf(clicked);
// ..IndexOf() returns -1 if nothign is found
if(indexOfButton > 0)
{
lbls[indexOfButton].DoWhatYouWant...
}
}
I am writing a simple calculator script for my C# programming class. It will of course have buttons 0-9 that will update the output textbox to add the number of whatever button is clicked. My problem right now that is I would rather not have to have 10 different click events in my script. I would rather have a loop that cycles through the buttons that will add the same click event to each one and then decide what number to add to the output based on the button.
So right now, I have a click event for the "1" button which is this...
private void btnNum1_Click(object sender, EventArgs e)
{
txtOutput.Text = Convert.ToString(txtOutput.Text + "1");
}
This works fine, but, again, I would rather not have to do this 10 times. How can I create a loop that prevents this?
The button names are btnNum1, btnNum2, btnNum3, etc.
Assuming the button text is just "1", "2" etc you could do this:
private void btnNum_Click(object sender, EventArgs e)
{
var button = sender as Button
txtOutput.Text += button.Content.ToString();
}
Then just apply this event to all the buttons.
Also note you don't need Convert.ToString() as what you are trying to convert is already a string. Using += also cleans up your code a bit.
You could do this to wire-up all of the events in one go:
for (var n = 0; n <= 9; n++)
{
var btn =
this
.Controls
.Find("btnNum" + n.ToString(), false)
.Cast<Button>()
.First();
var digit = n;
btn.Click += (s, e) =>
{
txtOutput.Text = digit.ToString();
};
}
You could enumerate the children controls of your Form/Control, look the type of controls which are type of Button and the name StartWith 'btnNum', with each of these buttons, add a Click event address to btnNum_Click().
Say if all your buttons are contained in a Panel named 'pnlButtons', you could loop all the children like this.
foreach (var control in pnlButtons.Controls)
{
if(control.GetType() == typeof(Button))
{
var button = control as Button;
if (button .Name.StartWith('btnNum'))
{
button.Click += btnNum_Click;
}
}
}
You can use the "Tag" property of the Button control and make an array of Buttons to subscribe to the same event. See sample below:
void InitializeButtons()
{
Button btnNum1 = new Button();
btnNum1.Text = "1";
btnNum1.Tag = 1;
//Button 2..8 goes here
Button btnNum9 = new Button();
btnNum9.Text = "9";
btnNum9.Tag = 9;
Button[] buttons = new Button[]{
btnNum1, btnNum2, btnNum3, btnNum4, btnNum5, btnNum6, btnNum7, btnNum8, btnNum9
};
for (int i = 0; i < buttons.Length; i++)
{
buttons[i].Click += Button_Click;
}
}
void Button_Click(object sender, EventArgs e)
{
Button button = (Button)sender;
int value = (int)button.Tag;
//Do something with value
}
Assuming WinForms, you can recursively search for buttons that start with "btnNum" and wire them up to a common handler like this:
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
this.Load += Form1_Load;
}
void Form1_Load(object sender, EventArgs e)
{
FindButtons(this);
}
private void FindButtons(Control ctl)
{
foreach(Control ctrl in ctl.Controls)
{
if (ctrl.Name.StartsWith("btnNum") && (ctrl is Button))
{
Button btn = (Button)ctrl;
btn.Click += btn_Click;
}
else if(ctrl.HasChildren)
{
FindButtons(ctrl);
}
}
}
private void btn_Click(object sender, EventArgs e)
{
Button btn = (Button)sender;
txtOutput.Text = Convert.ToString(txtOutput.Text + btn.Text);
}
}