I have tried to code a button such that it is disabled upon form loading however enabled once a textbox has had text entered. My code is below, which is probably familiar:
Public Form()
{
InitializeComponent();
this.button1.enabled = false;
}
private void textbox_TextChanged (object sender, EventArgs e)
{
button1.Enabled = !string.IsNullOrWhiteSpace(textbox.Text);
}
The button indeed loads up disabled, the enabling function doesn't work upon text input and I'm not sure what the issue could be. It is a modal form is that matters. I was wondering if maybe I needed an event listener (although I'm not certain how exactly they work).
Check your Designer.cs file and make sure you have event handler registration there. Something like this:
this.textBox.TextChanged += new System.EventHandler(this.textBox_TextChanged);
Will this work? I can't really see a problem with your code though...
button1.Enabled = textbox.Text != "";
I hope this helps.
May not be the solution to your problem, but this would be the fastest check for one's computer to perform (at least if you let the JIT compiler optimize your code):
button1.Enabled = textbox.Text.Length > 0;
try this
private void Form1_Load(object sender, EventArgs e)
{
button1.Enabled = false;
}
private void textBox1_TextChanged(object sender, EventArgs e)
{
if (string.IsNullOrEmpty(textBox1.Text))
{
button1.Enabled = true;
}
}
You could try either of the following on the TextChanged property of the TextBox :
private void textBox1_TextChanged(object sender, EventArgs e)
{
if (textbox.Text.Length > 0)
{
button1.Enabled = true;
}
else
button1.Enabled = false;
}
or, using the string.IsNullOrEmpty method:
private void textBox1_TextChanged(object sender, EventArgs e)
{
if (!string.IsNullOrEmpty(textbox.Text))
{
button1.Enabled = true;
}
else
button1.Enabled = false;
}
The the below line:
button1.Enabled = !string.IsNullOrWhiteSpace(textbox.Text);
If it didn't work for you or if you are getting an error, then probably because the IsNullOrWhiteSpace method was introduced in .NET 4
Related
I have a newbie question that's been bugging me. I've been messing around with forms in visual studio. In the simple program I'm making, I want to disable/enable a button depending on whether a checkbox is ticked.
Can someone tell me why this code doesn't work? Specifically the if statement.
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void Form1_Load(object sender, EventArgs e)
{
Do_Check();
}
private void checkBox1_CheckedChanged(object sender, EventArgs e)
{
Do_Check();
}
private void Do_Check()
{
// button1.Enabled = checkBox1.Checked;
if (checkBox1.Checked)
button1.Enabled = true;
}
private void button1_Click(object sender, EventArgs e)
{
MessageBox.Show("Blah blah");
}
}
I've commented out one way of achieving the desired result. I'm just not sure why the if statement doesn't also work. Any help would be appreciated.
Your button is only enabled if the checkBox1 is checked - but never disabled. Hence you should do something like this:
if (checkBox1.Checked)
button1.Enabled = true;
else
button.Enabled = false;
However, your commented solution with
button1.Enabled = checkBox1.Checked;
is way more elegant.
int sn = 0;
private void Form1_Load(object sender, EventArgs e)
{
label1.Text = "Konfigürasyon Yükleniyor.";
timer1.Interval = 1000;
timer1.Enabled = true;
timer1.Start();
}
private void timer1_Tick(object sender, EventArgs e)
{
if (sn == 3)
{
label1.Text = "Ayarlar Alınıyor";
}
if (sn == 5)
{
label1.Text = "Program Başlatılıyor";
}
sn++;
timer1.Stop();
}
When I open the form I want to change the label when I select the text range.
I assume that event handler is attached in designer to this timer1.
As far as I can understand, this label is never set, because you stop Timer after it hits first time.
In this case variable sn = 0 so non of if condition from your event handler is met.
I think to solve problem you sould remove this timer1.Stop() from event handler.
You probably want
private void timer1_Tick(object sender, EventArgs e) {
if (sn == 3)
label1.Text = "Ayarlar Alınıyor";
else if (sn == 5) {
label1.Text = "Program Başlatılıyor";
timer1.Stop(); // <- stop timer here on the 5th second, not on the 1st one
}
sn++;
}
Is this possible to display button on Windows Form only when focus is on specific textbox?
Tried that with this approach:
private void button3_Click(object sender, EventArgs e)
{
MessageBox.Show("OK");
}
private void textBox2_Enter(object sender, EventArgs e)
{
button3.Visible = true;
}
private void textBox2_Leave(object sender, EventArgs e)
{
button3.Visible = false;
}
No luck, because button click does not work then, because button is hidden immediately after textbox lost focus, preventing it from firing button3_Click(/*...*/) { /*...*/ } event.
Now I'm doing it like that:
private void button3_Click(object sender, EventArgs e)
{
MessageBox.Show("OK");
}
private void textBox2_Enter(object sender, EventArgs e)
{
button3.Visible = true;
}
private void textBox2_Leave(object sender, EventArgs e)
{
//button3.Visible = false;
DoAfter(() => button3.Visible = false);
}
private async void DoAfter(Action action, int seconds = 1)
{
await Task.Delay(seconds*1000);
action();
}
Form now waits for a second and only then hides button3.
Is there any better approach?
I think you want to display the button only when focus is on specific textbox or the focus is on the button.
To do this you can check the Focused property of button3 in the Leave event of textBox2 and only hide the button if the button doesn't have focus. Note that the button will get focus before the Leave event of textBox2 fires.
You will then need to hide the button in the scenario where button3 loses focus and the focus moves to somewhere other than textBox2. You can use exactly the same technique here by handling the Leave event of button3 and only hiding button3 if textBox2 does not have focus.
The following code should fit your requirements:
private void textBox2_Leave(object sender, EventArgs e)
{
if (!button3.Focused)
{
button3.Visible = false;
}
}
private void button3_Leave(object sender, EventArgs e)
{
if (!textBox2.Focused)
{
button3.Visible = false;
}
}
private void textBox2_Enter(object sender, EventArgs e)
{
button3.Visible = true;
}
private void button3_Click(object sender, EventArgs e)
{
MessageBox.Show("Button clicked");
}
Why not work with the GotFocus and LostFocus event of the TextBox?
private void textBox2_GotFocus(object sender, EventArgs e)
{
button3.Visible = true;
}
Then hide the button on the click event.
private void button3_Click(object sender, EventArgs e)
{
MessageBox.Show("OK");
button3.Visible = false;
}
How about you add a Panel and place the button and text boxes in that panel and when user MouseHovers that Panel then display the button...
This way user would be able to click on the button...
This is the event you are looking for, I think...
http://msdn.microsoft.com/en-us/library/system.windows.forms.control.mousehover(v=vs.110).aspx
UPDATE:
var textboxFocussed = false;
private void textBox2_Enter(object sender, EventArgs e)
{
textboxFocussed = true;
}
private void textBox2_Leave(object sender, EventArgs e)
{
textboxFocussed = false;
}
UPDATE 2
private void Panel_GotFocus(object sender, EventArgs e)
{
button3.Visible = textboxFocussed;
}
private void Panel_LostFocus(object sender, EventArgs e)
{
button3.Visible = false;
}
Here are the details of the Panel Events
you can add Enter event handler for all controls on form at Load. Just make sure to skip the controls on which you want to show the button.
List<string> strControlException = new List<string>();
public Form1()
{
InitializeComponent();
strControlException.Add("btnMain");
strControlException.Add("txtMain");
}
private void Form1_Load(object sender, EventArgs e)
{
for (int i = 0; i < this.Controls.Count;i++ )
{
if (!strControlException.Contains(Controls[i].Name))
{
Controls[i].Enter += new EventHandler(hideButton);
}
}
}
private void txtMain_Enter(object sender, EventArgs e)
{
btnMain.Visible = true;
}
private void hideButton(object sender, EventArgs e)
{
btnMain.Visible = false;
}
btnMain (Button you want to Manipulate) and txtMain (Which controls the vibility of the button) are the controls in contention here
Add more controls on the form to test.
Explanation for the above code :
First initialize a list with the names of controls that should show the Button
On Form Load add an Event handler to all controls (except the one in our list)
In the handler function hide the button. (You might want to perform more logic here based on the control that called this function)
Button is hidden by default and only on textbox Enter event we show the button.
I have two checkboxes on my form; chkBuried and chkAboveGround. I want to set it up so if one is checked, the other is unchecked. How can I do this?
I have tried the CheckChanged property:
private void chkBuried_CheckedChanged(object sender, EventArgs e)
{
chkAboveGround.Checked = false;
}
private void chkAboveGround_CheckedChanged(object sender, EventArgs e)
{
chkBuried.Checked = false;
}
And it works, just not as well as I hoped. That is, when I check chkBuried, then check chkAboveGround, both boxes become unchecked before I can check another one again.
modify your code as below.
private void chkBuried_CheckedChanged(object sender, EventArgs e)
{
chkAboveGround.Checked = !chkBuried.Checked;
}
private void chkAboveGround_CheckedChanged(object sender, EventArgs e)
{
chkBuried.Checked = !chkAboveGround.Checked;
}
I suggest you use check_click instead of check_changed
private void checkBox1_Click(object sender, EventArgs e)
{
checkBox2.Checked = false;
checkBox3.Checked = false;
}
private void checkBox2_Click(object sender, EventArgs e)
{
checkBox1.Checked = false;
checkBox3.Checked = false;
}
private void checkBox3_Click(object sender, EventArgs e)
{
checkBox1.Checked = false;
checkBox2.Checked = false;
}
The reason for the behavior you have explained is that you are using CheckedChanged event, which means that when you are setting the Checked property of a CheckBox manually, the event is also fired, causing another box to react again.
Therefore, the following might help you:
private void chkBuried_CheckedChanged(object sender, EventArgs e)
{
if (chkBuried.Checked == true) {
chkAboveGround.Checked = false;
} else {
chkAboveGround.Checked = true;
}
}
private void chkAboveGround_CheckedChanged(object sender, EventArgs e)
{
if (chkAboveGround.Checked == true) {
chkBuried.Checked = false;
} else {
chkBuried.Checked = true;
}
}
UPDATE 29.03.2020: functionally the code in my answer is the same as the answer given by Riz. Nevertheless, I am leaving the code as I put it originally since it might make the whole situation easier to understand for the people who are new to coding. If you are to implement anything similar in production code, please use the answer by Riz as an example.
I would prefer radio buttons, but you can do something like this:
public void CheckACheckBox(Checkbox ck)
{
foreach (Control ckb in this.Controls)
{
if ((ckb is CheckBox) && (ckb == ck))
ck.Checked = true;
else
ck.Checked = false;
}
}
List<CheckBox> groupOfCheckBoxes = new List<CheckBox>();
void InitFunction() {
groupOfCheckBoxes.Add(checkbox1);
groupOfCheckBoxes.Add(checkbox2);
groupOfCheckBoxes.Add(checkbox3);
foreach (CheckBox cb in groupOfCheckBoxes)
cb.Click += checkbox_Click
}
void checkbox_Click(object sender, EventArgs e)
{
foreach (CheckBox cb in groupOfCheckBoxes) {
cb.IsChecked = cb == sender;
}
}
However I would suggest radio boxes as well.
The code above is untested and may have some typos
Better version, allows the user to uncheck boxes.
private void chkOne_CheckedChanged(object sender, EventArgs e)
{
if (chkTwo.Checked == true)
{
chkTwo.Checked = !chkOne.Checked;
}
}
private void chkTwo_CheckedChanged(object sender, EventArgs e)
{
if (chkOne.Checked == true)
{
chkOne.Checked = !chkTwo.Checked;
}
}
The best option and easiest way for me was to create a Click event instead of a CheckedChanged event.
This method works perfectly with two or more checkbox and allows to have them all unchecked.
private void chkOne_Click(object sender, EventArgs e)
{
chkTwo.Checked = false;
}
private void chkTwo_Click(object sender, EventArgs e)
{
chkOne.Checked = false;
}
This will work for two unchecked boxes, since they are already unchecked it is simpler.
I had to do this myself also.
private void customer_IsCheckedChanged(object sender, EventArgs e)
{
business.IsChecked = false;
}
private void business_IsCheckedChanged(object sender, EventArgs e)
{
customer.IsChecked = false;
}
I needed to show or not show a table when activating the CheckBox, how they were two, if I activated both, everything was fine, but if I tried to deactivate one later, the other was also deactivated. PD: The default value for the tables that I used was Visible=false. The solution I got was the following:
protected void YourNameOfMethodForBothCheckBox(object sender, EventArgs e)
{
if (CheckBox_1.Checked == true)
{
Table_1.Visible = true;
if (CheckBox_2.Checked == true)
{
Table_2.Visible = true;
}
else { Table_2.Visible = false; }
}
else
{
Table_1.Visible = false;
if (CheckBox_2.Checked == false)
{
Table_2.Visible = false;
}
else
{
Table_2.Visible = true;
}
}
}
I have a GridView that has a column with RepositoryItemCheckEdit as ColumnEdit. I want to disable this control for just one row. How can I do this? Any suggestions?
I have found a solution to the problem.
gridView1.CustomRowCellEditForEditing += OnCustomRowCellEditForEditing;
private void OnCustomRowCellEditForEditing(object sender, CustomRowCellEditEventArgs e)
{
if (e.Column.FieldName != "MyFieldName") return;
*code here*
e.RepositoryItem.ReadOnly = true;
}
you can make the editor read only by handling CustomRowCellEdit:
private void gridView1_CustomRowCellEdit(object sender, CustomRowCellEditEventArgs e)
{
if(code goes here)
e.RepositoryItem.ReadOnly = true;
}
you can also prevent the editor from being show by handling ShowingEditor:
private void gridView1_ShowingEditor(object sender, CancelEventArgs e)
{
if (code goes here)
e.Cancel = true;
}
in the class that inherits DataGridViewColum override method InitializeEditingControl
it has parameter rowIndex the write something like this
this.DataGridView.EditingControl.Enbale = rowIndex != 3; // or the number you need