I am making a Windows Forms application with algorithms for school and I want to add some nice functionality to display that the algorithm is working well. One of those things is that when the user selects an item in one listbox, the items that are part of that one item get automatically selected in another listbox. This is done by the application.
I would like it if the user could not select another item in the listbox that is automatically monitored, but enabled = false sets the color to gray which makes the text invisible when an item is automatically selected.
Is there any other way to achieve this?
What you could do is
When the program selects an entry in the second list, set a flag
When an entry in the list is selected, read that flag
If the flag is not set, unselect the item
Unset the flag
Code wise, this equates to something like the following (please note that I would not write code like this in a real-world szenario, but to get the gist of it, it should suffice)
private bool _valueIsSetProgrammatically = false;
private void listBox1_SelectedValueChanged(object sender, EventArgs e)
{
this._valueIsSetProgrammatically = true;
this.listBox2.SelectedItem = this.listBox1.SelectedItem;
}
private void listBox2_SelectedValueChanged(object sender, EventArgs e)
{
if (!this._valueIsSetProgrammatically)
{
this.listBox2.SelectedItem = null;
}
this._valueIsSetProgrammatically = false;
}
Please note that this snippet unselects the second listbox. If you'd like to retain the selected item, you could change the second method to
private void listBox2_SelectedValueChanged(object sender, EventArgs e)
{
if (!this._valueIsSetProgrammatically)
{
this.listBox2.SelectedItem = this.listBox1.SelectedItem;
}
this._valueIsSetProgrammatically = false;
}
(Technically the flag is not needed in this case, you could simply set the SelectedItem of listBox2 to the SelectedItem of listBox1.)
I'm trying to make a 'show password' checkbox underneath my textbox-Password to unmask the txtpassword and show the characters.
protected void chkUnmask_CheckedChanged(object sender, EventArgs e)
{
if (chkUnmask.Checked == true)
{
txtPassword.TextMode = TextBoxMode.Password;
}
else
{
txtPassword.TextMode = TextBoxMode.Password;
}
}
I use If-Else condition to change the behavior of the textbox everytime the checkbox change to checked and unchecked. It works fine with WindowsFormApp C#, but in WebApp C# ASP.net doesn't, I tried to restart the visual studio and my laptop hoping it's just a bug but still doesn't work.. I wonder if my coding was wrong.
How would the result be different if both if conditions are
txtPassword.TextMode = TextBoxMode.Password;
}
You need to change the TextBox mode for one of the conditions
// I think you need to set break points and check if this line is being triggered
TextBox1.TextMode = TextBoxMode.SingleLine;
// you can try this code which works fine. Add a button, and a textbox and set its textmode to Password. Type something the then click the button.
protected void Button1_Click1(object sender, EventArgs e)
{
TextBox1.TextMode = TextBoxMode.SingleLine;
}
I am building a WinForms Application in C# .NET
The WinForms Application has a ComboBox where the DropDownStyle is set to DropDownList. When the App is launched, I read an XML file to populate the values of the ComboBox. And, at this time, nothing is selected in the ComboBox by default. As a result, buttons Change and Delete are disabled.
Now, when the user selects a value, I want the buttons Change and Delete to be enabled. So far I have accomplished (although, I am not sure that I have done it in the right way).
I have written the code in the SelectionChangeCommitted Event.
private void cbList_SelectionChangeCommitted(object sender, EventArgs e)
{
if (cbList.SelectedItem != null)
{
this.btnModify.Enabled = true;
this.btnRemove.Enabled = true;
}
else
{
this.btnModify.Enabled = false;
this.btnRemove.Enabled = false;
}
}
Now, when I chose a value...the buttons get enabled (as expected). The user then clicks on Delete button and we remove the selected value. Now, there is nothing Selected in the cbList but the buttons are still enabled?
What is the function/event where I check if a value is selected or not and then enable/disable the buttons.
At the moment, dont have Visual Studio, so I dont remember which events we have. But you can make this,
private void CheckButtons()
{
if (cbList.SelectedItem != null)
{
this.btnModify.Enabled = true;
this.btnRemove.Enabled = true;
}
else
{
this.btnModify.Enabled = false;
this.btnRemove.Enabled = false;
}
}
and use your func in event
private void cbList_SelectionChangeCommitted(object sender, EventArgs e)
{
CheckButtons();
}
as you said, after deleting, buttons are still visible, so you can put CheckButtons() function after your delete function like
DeleteX();
CheckButtons();
Ok so I'm trying to move items from one listbox to another by using multiple buttons i.e
I have 2 buttons cmdRight and cmdRight2 which are both disabled on form load
If the user selects a single item on the first listbox a cmdRIght button enables but cmdRight2 is still disabled , if the user selects multiple items on the first listbox a cmdRight2 button enables but cmdRight is disabled.
I've got the move buttons to work but the problem I'm having is after moving multiple items with the cmdRight2 button the cmdRight button enables (which it shouldn't it should only enable after selecting a single item in the listbox). I've tried numerous if statements etc. and yet it still happens.
I'm new to C# so any help would be appreciated.
Thank You
private void lbList1_SelectedIndexChanged(object sender, EventArgs e)
{
if (this.lbList1.SelectedItems != null)
{
cmdRight.Enabled = true; //enable cmdRight
cmdClear.Enabled = true; //enable cmdClear
if (this.lbList1.SelectedItems.Count > 1)//if multiple items selected
{
cmdRight.Enabled = false;
cmdRight2.Enabled = true; //enable cmdRight2
}
}
}
private void cmdRight2_Click(object sender, EventArgs e)
{
foreach (int i in lbList1.SelectedIndices)
{
lbList2.Items.Add(lbList1.Items[i].ToString());
}
while (lbList1.SelectedItems.Count > 0)
{
lbList1.Items.Remove(lbList1.SelectedItems[0]);
}
cmdRight2.Enabled = false;
}
private void cmdRight_Click(object sender, EventArgs e)
{
lbList2.Items.Add(lbList1.SelectedItem); //Add selected item from list1 to list2
lbList1.Items.Remove(lbList1.SelectedItem);//remove the selected item in list1
cmdRight.Enabled = false; //disable cmdRight
}
How about creating one method EnableButtons that enables/disables to buttons according to given criteria like "enable cmdRight2 only if.... is true".
Then, call the method whenever some of the criteria might change. The advantage of this over the way you're doing it now is that the criteria within the method are "absolute" (in that the buttons are either enabled or disabled in one go) instead of "relative" (enable the button when the user does this or that).
You could also call this method from the Application.Idle event instead of calling it in response to some user action.
EDIT
Declare the following method:
private void EnableButtons()
{
controlX.Enabled = (<condition...>);
controlY.Enabled = (<condition...>);
}
You can either invoke that method from the positions in code where something should change in the buttons' enabled states, or you can do the following in the constructor of the form:
public Form1()
{
// Other code...
Application.Idle += new <The respective event handler>;
}
Then, declare a method with the respective signature for the event and call EnableButtons there. This method would be called in situations where your application is "idle" (waiting for user actions).
I think you want
if (this.lbList1.SelectedItems.Count == 1)
{
}
else if(this.lbList1.SelectedItems.Count > 1)
{
}
else
{
}
instead of
if (this.lbList1.SelectedItems != null)
Then you could place all of this in a method called "EnableButtons" as mentioned elsewhere
The problem is that you are removing the items one by one, so when only one item is left, you essentially have one item selected so your program enables the cmdRight. The easiest way around this is to have
cmdRight2.Enabled = false;
cmdRight.Enabled = false;
at the end of the cmdRight2_Click method.
Is there a way to disable a tab in a TabControl?
Cast your TabPage to a Control, then set the Enabled property to false.
((Control)this.tabPage).Enabled = false;
Therefore, the tabpage's header will still be enabled but its contents will be disabled.
The TabPage class hides the Enabled property. That was intentional as there is an awkward UI design problem with it. The basic issue is that disabling the page does not also disable the tab. And if try to work around that by disabling the tab with the Selecting event then it does not work when the TabControl has only one page.
If these usability problems do not concern you then keep in mind that the property still works, it is merely hidden from IntelliSense. If the FUD is uncomfortable then you can simply do this:
public static void EnableTab(TabPage page, bool enable) {
foreach (Control ctl in page.Controls) ctl.Enabled = enable;
}
You can simply use:
tabPage.Enabled = false;
This property is not shown, but it works without any problems.
You can program the Selecting event on TabControler to make it impossible to change to a non-editable tab:
private void tabControler_Selecting(object sender, TabControlCancelEventArgs e)
{
if (e.TabPageIndex < 0) return;
e.Cancel = !e.TabPage.Enabled;
}
You could register the "Selecting" event and cancel the navigation to the tab page:
private void tabControl1_Selecting(object sender, TabControlCancelEventArgs e)
{
if (e.TabPage == tabPage2)
e.Cancel = true;
}
Another idea is to put all the controls on the tabpage in a Panel control and disable the panel! Smiley
You could also remove the tabpage from the tabControl1.TabPages collection. That would hide the tabpage.
Credits go to littleguru # Channel 9.
Presumably, you want to see the tab in the tab control, but you want it to be "disabled" (i.e., greyed, and unselectable). There is no built-in support for this, but you can override the drawing mechanism to give the desired effect.
An example of how to do this is provided here.
The magic is in this snippet from the presented source, and in the DisableTab_DrawItem method:
this.tabControl1.DrawMode = TabDrawMode.OwnerDrawFixed;
this.tabControl1.DrawItem += new DrawItemEventHandler( DisableTab_DrawItem );
Extending upon Cédric Guillemette answer, after you disable the Control:
((Control)this.tabPage).Enabled = false;
...you may then handle the TabControl's Selecting event as:
private void tabControl_Selecting(object sender, TabControlCancelEventArgs e)
{
e.Cancel = !((Control)e.TabPage).Enabled;
}
This will remove the tab page, but you'll need to re-add it when you need it:
tabControl1.Controls.Remove(tabPage2);
If you are going to need it later, you might want to store it in a temporary tabpage before the remove and then re-add it when needed.
The only way is to catch the Selecting event and prevent a tab from being activated.
The most tricky way is to make its parent equals null (make the tab alone without parent):
tabPage.Parent = null;
And when you want to return it back (will return it back at the end of pages collection) :
tabPage.Parent = tabControl;
And if you want to return it back in a specific location among the pages you can use :
tabControl.TabPages.Insert(indexLocationYouWant, tabPage);
I had to handle this a while back. I removed the Tab from the TabPages collection (I think that's it) and added it back in when the conditions changed. But that was only in Winforms where I could keep the tab around until I needed it again.
I've removed tab pages in the past to prevent the user from clicking them. This probably isn't the best solution though because they may need to see that the tab page exists.
Using events, and the properties of the tab control you can enable/disable what you want when you want. I used one bool that is available to all methods in the mdi child form class where the tabControl is being used.
Remember the selecting event fires every time any tab is clicked. For large numbers of tabs a "CASE" might be easier to use than a bunch of ifs.
public partial class Form2 : Form
{
bool formComplete = false;
public Form2()
{
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e)
{
formComplete = true;
tabControl1.SelectTab(1);
}
private void tabControl1_Selecting(object sender, TabControlCancelEventArgs e)
{
if (tabControl1.SelectedTab == tabControl1.TabPages[1])
{
tabControl1.Enabled = false;
if (formComplete)
{
MessageBox.Show("You will be taken to next tab");
tabControl1.SelectTab(1);
}
else
{
MessageBox.Show("Try completing form first");
tabControl1.SelectTab(0);
}
tabControl1.Enabled = true;
}
}
}
I've solved this problem like this:
I've got 3 tabs and I want to keep user at the first tab if he didnt log in,
so on the SelectingEvent of TabControl I wrote
if (condition) { TabControl.Deselect("2ndPage"); TabControl.Deselect("3dPage"); }
The user cannot click on tabs to navigate, but they can use the two buttons (Next and Back). The user cannot continue to the next if the //conditions are no met.
private int currentTab = 0;
private void frmOneTimeEntry_Load(object sender, EventArgs e)
{
tabMenu.Selecting += new TabControlCancelEventHandler(tabMenu_Selecting);
}
private void tabMenu_Selecting(object sender, TabControlCancelEventArgs e)
{
tabMenu.SelectTab(currentTab);
}
private void btnNextStep_Click(object sender, EventArgs e)
{
switch(tabMenu.SelectedIndex)
{
case 0:
//if conditions met GoTo
case 2:
//if conditions met GoTo
case n:
//if conditions met GoTo
{
CanLeaveTab:
currentTab++;
tabMenu.SelectTab(tabMenu.SelectedIndex + 1);
if (tabMenu.SelectedIndex == 3)
btnNextStep.Enabled = false;
if (btnBackStep.Enabled == false)
btnBackStep.Enabled = true;
CannotLeaveTab:
;
}
private void btnBackStep_Click(object sender, EventArgs e)
{
currentTab--;
tabMenu.SelectTab(tabMenu.SelectedIndex - 1);
if (tabMenu.SelectedIndex == 0)
btnBackStep.Enabled = false;
if (btnNextStep.Enabled == false)
btnNextStep.Enabled = true;
}
tabControl.TabPages.Remove(tabPage1);
This is an old question, but someone may benefit from my addition. I needed a TabControl that would show hidden tabs successively (after an action was performed on the current tab). So, I made a quick class to inherit from and called HideSuccessive() on Load:
public class RevealingTabControl : TabControl
{
private Action _showNextRequested = delegate { };
public void HideSuccessive()
{
var tabPages = this.TabPages.Cast<TabPage>().Skip(1);
var queue = new ConcurrentQueue<TabPage>(tabPages);
tabPages.ToList().ForEach(t => t.Parent = null);
_showNextRequested = () =>
{
if (queue.TryDequeue(out TabPage tabPage))
tabPage.Parent = this;
};
}
public void ShowNext() => _showNextRequested();
}
There is the XtraTabPage.PageEnabled property allowing you to disable certain pages.
Here the solution that i implement:
private void switchTapPage(TabPage tabPage)
{
foreach(TabPage page in tabControl1.TabPages)
{
tabControl1.TabPages.Remove(page);
}
tabControl1.TabPages.Add(tabPage);
}
Basically, i just call this method sending the tabPage that i currently need to show, the method will remove all the tabPages on the tabControl and after that it will just add the one that i sent it.
So the rest of the tabHeaders will not shown and they will be inaccessible, because they dont even exists in the tabControl.
I took the idea from the #stormenet answer.
You can do it through the tabpages: tabPage1.Hide(), tabPage2.Show() etc.
In the form load event if we write this.tabpage.PageEnabled = false, the tabpage will be disabled.
Assume that you have these controls:
TabControl with name tcExemple.
TabPages with names tpEx1 and tpEx2.
Try it:
Set DrawMode of your TabPage to OwnerDrawFixed;
After InitializeComponent(), make sure that tpEx2 is not enable by adding this code:
((Control)tcExemple.TabPages["tpEx2").Enabled = false;
Add to Selection tcExemple event the code below:
private void tcExemple_Selecting(object sender, TabControlCancelEventArgs e)
{
if (!((Control)e.TabPage).Enabled)
{
e.Cancel = true;
}
}
Attach to DrawItem event of tcExemple this code:
private void tcExemple_DrawItem(object sender, DrawItemEventArgs e)
{
TabPage page = tcExemple.TabPages[e.Index];
if (!((Control)page).Enabled)
{
using (SolidBrush brush = new SolidBrush(SystemColors.GrayText))
{
e.Graphics.DrawString(page.Text, page.Font, brush, e.Bounds);
}
}
else
{
using (SolidBrush brush = new SolidBrush(page.ForeColor))
{
e.Graphics.DrawString(page.Text, page.Font, brush, e.Bounds);
}
}
}
It will make the second tab non-clickable.
I could not find an appropriate answer to the question. There looks to be no solution to disable the specific tab. What I did is to pass the specific tab to a variable and in SelectedIndexChanged event put it back to SelectedIndex:
//variable for your specific tab
int _TAB = 0;
//here you specify your tab that you want to expose
_TAB = 1;
tabHolder.SelectedIndex = _TAB;
private void tabHolder_SelectedIndexChanged(object sender, EventArgs e)
{
if (_TAB != 0) tabHolder.SelectedIndex = _TAB;
}
So, you don't actually disable the tab, but when another tab is clicked it always returns you to the selected tab.
in C# 7.0, there is a new feature called Pattern Matching. You can disable all tabs via Type Pattern.
foreach (Control control in Controls)
{
// the is expression tests the variable and
// assigned it to a new appropriate variable type
if (control is TabControl tabs)
{
tabs.Enabled = false;
}
}
Use:
tabControl1.TabPages[1].Enabled = false;
By writing this code, the tab page won't be completely disabled (not being able to select), but its internal content will be disabled which I think satisfy your needs.
The solution is very simple.
Remove/comment this line
this.tabControl.Controls.Add(this.YourTabName);
in IntializeComponent() method in MainForm.cs
MyTabControl.SelectedTab.Enabled = false;