I'm creating a simple notepad type of application with the tab functionality. I'm creating the TabControl, its TabPages and RichTextBoxes at run-time. I have them instantiated at class scope. And there is a MenuStrip item called New, by clicking that you can add more tab pages.
TabControl tbcEditor = new TabControl();
TabPage tbPage = new TabPage();
RichTextBox rtb = new RichTextBox();
private void frmTextEditor_Load(object sender, EventArgs e)
{
Controls.Add(tbcEditor);
tbcEditor.Dock = DockStyle.Fill;
tbcEditor.TabPages.Add(tbPage);
tbPage.Controls.Add(rtb);
rtb.Dock = DockStyle.Fill;
}
private void newToolStripMenuItem_Click(object sender, EventArgs e)
{
//TabPage tbPage = new TabPage();
//RichTextBox rtb = new RichTextBox();
tbPage.Controls.Add(rtb);
rtb.Dock = DockStyle.Fill;
tbcEditor.TabPages.Add(tbPage);
}
The problem I'm facing is a bit difficult to explain. I'll try my best. When the form loads, everything works as expected. The TabControl creates with a TabPage with a RichTextBox added. However if I click that New button to add another page, it goes bonkers. A new TabPage gets created but without a RichTextBox added. No errors are thrown either. If I un-comment out those 2 lines(under MenuItem click event), which creates 2 instances of TabPage and RichTextBox, everything works as I want.
Now my first question is why do I have to make new instances of only those 2 types(TabPage, RichTextBox) again but not TabControl? As you can see in the last line, I can use tbcEditor once again. But not tbPage and rtb.
Sure I can go on declaring them again at local scope but another issue arises then. If I want to say, add copy, paste functionality, I should do something like this,right?
Clipboard.SetDataObject(rtb.SelectedText);
But I can't access rtb since it is declared as local.
I'm very baffled by this so any suggestions, ideas on how to overcome these 2 issues would be greatly appreciated.
Thank you.
If I un-comment out those 2 lines(under MenuItem click event), which creates 2 instances of TabPage and RichTextBox, everything works as I want.
When you uncomment those lines, you are adding the same instance of the rich textbox and tab page to the container panel again which is meaningless. Instead add new controls foreach tabpage. (I hope thats the requirement)
Now my first question is why do I have to make new instances of only those 2 types(TabPage, RichTextBox) again but not TabControl?
TabControl is the parent control which has TabPages as child controls. You can have multiple tabs under one TabControl. So you need not create TabControls other than the tbcEditor you have already added. We do not add container controls more than once (unless its the requirement). Do we need more forms? No, just one form which can hold all the child controls right. Similarly just one TabControl which can hold a collection of TabPages. You would need more TabControls only if you want sub-tabs foreach new tab which I guess is not the requirement..
But I can't access rtb since it is declared as local.
This is no big deal. You can do in two ways:
1) Search for your appropriate control by looping. The SelectedTab property gives what you want.
private void someEvent(object sender, EventArgs e)
{
foreach (Control c in tbcEditor.SelectedTab.Controls)
{
if (c is RichTextBox)
{
Clipboard.SetDataObject(((RichTextBox)c).SelectedText);
break; //assuming u have just one main rtb there
}
}
}
2) Tag each rtb to the tabPage when you create it, and then you can get the tag element of the selected tab page to get the rich text box. I would go for this approach.
Edit: (In general pls make the following changes too to your code):
TabControl tbcEditor = new TabControl();
private void frmTextEditor_Load(object sender, EventArgs e)
{
Controls.Add(tbcEditor);
tbcEditor.Dock = DockStyle.Fill;
AddMyControlsOnNewTab();
}
private void AddMyControlsOnNewTab()
{
TabPage tbPage = new TabPage();
RichTextBox rtb = new RichTextBox();
tbPage.Tag = rtb; //just one extra bit of line.
tbcEditor.TabPages.Add(tbPage);
tbPage.Controls.Add(rtb);
rtb.Dock = DockStyle.Fill;
}
private void newToolStripMenuItem_Click(object sender, EventArgs e)
{
AddMyControlsOnNewTab();
}
Now, you can call it like this:
private void someEvent(object sender, EventArgs e)
{
RichTextBox rtb= (RichTextBox)tbcEditor.SelectedTab.Tag;
Clipboard.SetDataObject(rtb.SelectedText);
//or even better in just a line,
//Clipboard.SetDataObject(((RichTextBox)tbcEditor.SelectedTab.Tag).SelectedText);
}
What you have to consider here is which is the control that you first get and which is the one you do not get. You would get TabPage anyways but not the RichTextBox. So you have to tag RichTextBox to TabPage. You have to cast it since Tag is of type object, so you have to specify which kind of object it is. Finally, this method has the advantage that you need not loop through a list, so its more performant. And that you can have more RichTextBoxes in the TabPage (provided you want to copy text from only one set of RichTextBoxes, one from each TabPage)..
The commented lines are doing just what they are suppposed to do. The code does not associate the Richtextbox with the Tabpage .
TabPage tbPage = new TabPage(); // Creates a new tabpage
RichTextBox rtb = new RichTextBox(); // Creates a new RichtextBox control.
TabControl is a container , so one instance is just fine.
Also see this - http://sujay-ghosh.blogspot.in/2009/03/addingremoving-dynamically-created.html, nothing with do with tabcontrols, but how to create controls on the fly.
Hope this helps .
The code
tbPage.Controls.Add(rtb);
rtb.Dock = DockStyle.Fill;
tbcEditor.TabPages.Add(tbPage);
Takes your exisitng textbox, adds it to the exisitng tab page, then adds that existing tab page to the editor. Since this has already been done, nothing happens.
When you add those two lines, you create new instances of the text box and a new tab page, which is exactly what you want. Your latter problem comes, because the newly declared variable rtb hides the one declared in the class -- in a different method you can only access the onde declared in the class (barring getting the control out of the tab)
To get around not being able to access the proper text box, you can maintain them in a list(*) (or some other collection) and refer to the one associated with the currently active tab. For this, you will have to create an event listener to see which tab is activated currectly.
(*) as opposed to having only one
OK you need to create fresh instances of the RichTextBox rathere than trying to add the same instance to each tab.
TabControl tbcEditor = new TabControl();
//Get rid off this line --- TabPage tbPage = new TabPage();
//Get rid off this line --- RichTextBox rtb = new RichTextBox();
List<TabPage> _tabs = new List<TabPage>();
List<RichTextBox> _tbx = new List<RichTextBox>();
private void frmTextEditor_Load(object sender, EventArgs e)
{
Controls.Add(tbcEditor);
tbcEditor.Dock = DockStyle.Fill;
AddNewTab();
}
private void newToolStripMenuItem_Click(object sender, EventArgs e)
{
AddNewTab();
}
private void AddNewTab()
{
//TabPage
var tbPage = new TabPage();
_tabs.Add(tbPage);
//RichTextBox
var rtb = new RichTextBox();
_tbx.Add(rtb);
tbPage.Controls.Add(rtb);
rtb.Dock = DockStyle.Fill;
tbcEditor.TabPages.Add(tbPage);
}
This simply add both the tab and the rtb to a collection which can be accessed by index (can also use Dictionary for named access etc). There are other ways of course, including just nameing the components and looping through for them when required etc.
Related
I'm trying to find a a way to be able to essentially dynamically generate code based on an input.
For example I could type something like:
int Number = 22;
Button<Number>.Text = "X";
So in this case it would set button22 to have its text be an "X".
And I could change it so that I could input, for example 24 into the program and it would then set button24 to be an "X", instead of setting up a bunch of if statements to cover every potential button press.
For further context I have a Grid of 64 buttons and I need to be able to edit them individually to show to the user which buttons have been pressed, it is possible to do it with a lot of if statements but I thought it might be worth trying to find a more elegant solution.
You could have a list of buttons:
private List<Button> _buttons = new List<Button>();
Populate it like this:
for (int i = 0; i < 10; i++)
{
var b = new Button();
b.Text = $"Button #{i}";
b.Click += HandleButtonClick;
}
And you could even set an event handler on one of its events which doesn't even need to use the list (the sender is the source of the event):
private void HandleButtonClick(object sender, EventArgs e)
{
(sender as Button).Text = "X";
}
Buttons have a Tag property that can be used to hold arbitrary data about a button, this is described for WinForms, WPF and UWP.
Simple usage that is similar to OP's requirement is demonstrated in this SO post
This situation is in a practical sense the very reason that .Tag exists at all in user interface controls pretty much from the birth of c#.
So you do not need to use a custom class for a button, just simply assign your value to the .Tag property on the Button class that you are creating programmatically:
in this example a list is used to create the buttons and separate the creation from the layout, it is not necessary to do this, but may be useful. Instead, you could assign this button to it's parent container and/or set the layout margins or coordinates without keeping a reference to the Button object at all.
If OP updates the post to include implementation examples, we can update this response with more specific and complete code.
private List<Button> _buttons = new List<Button>();
// ... iteration or switching logic
var nextButton = new Button
{
Text = "x",
Tag = 22
};
nextButton.Click += DynamicButton_Click;
_buttons.Add(nextButton);
// ... later push the buttons into the parent container or bind to the UI
Then the button click handler you can access this Tag property:
this is presented from WinForms, the only difference in UWP or WPF is the method signature, change EventArgs to RoutedEventArgs
private void DynamicButton_Click(object sender, EventArgs e)
{
if(int.TryParse((sender as Button).Tag?.ToString(), out int buttonValue))
{
// use buttonValue
Console.Out.WriteLine(buttonValue);
}
else
{
// Otherwise, sender was not a button, or the button did not have an integer tag value
// either way, handle that error state here...
}
}
Using these concepts, once the buttons are created, let's say in some simple grid alignment, you could allow the user to set this Tag value at runtime if you have a TextBox (or other) input field that can be accessed from the code.
I recommend that you use MVVM style bindings for this rather than directly referencing a TextBox control, but this is simply to demonstrate the point.
private void DynamicButton_Click(object sender, EventArgs e)
{
// assign the string value from the ButtonValueTextbox control to this button
string value = this.ButtonValueTextBox.Text;
if(sender is Button button)
{
button.Tag = value;
}
else
{
// Otherwise, sender was not a button
// handle the error state here if you need to...
}
}
Now that each button has a tag, you could easily add logic to maintain unique tag values by iterating through the other buttons and clearing the tag if it was previously assigned to a different button.
Maybe you could keep a List of Button References:
var myButtons = new List<Button>();
myButtons.Add(firstButton);
myButtons.Add(secondButton);
// ... etc
// ... then somewhere else
int number = 3;
myButtons[number].Text = "xxx";
I am working on making a music player in c#. I am making music playlists right now and am stuck. As of right now I am using tabControl and a button that adds a tab with an empty listbox in it. Here is the code for that button:
private void button10_Click(object sender, EventArgs e)
{
TabPage tp = new TabPage("Playlist");
tabControl1.TabPages.Add(tp);
ListBox lb = new ListBox();
lb.Dock = DockStyle.Fill;
tp.Controls.Add(lb);
}
The problem I am running into is that I do not know how to allow the user to add music to these dynamically created listboxes within the tabs. The main list of music is located in a listbox in the first tab and I want the user to be able to select this music and put it in the new listboxes or "playlists" so I need to reference them somehow.
I'll just assume that you have a button (addToPlayListButton), a textBox (playListName) to add the selected song to the entered playList (tab-) name and that your songs listBox is called songList. I'll furthermore assume that every new playlist has a new tab. In that case you'll have to identify them so I'd change the name of the tabs:
TabPage tp = new TabPage($"Playlist {tabControl1.TabPages.Count}");
So you'll have to handle the button click event from addToPlayListButton like that:
private void onAddToPlayListButton_Click (object sender, EventArgs e) =>
(tabControl1.TabPages.Cast<TabPage>()
.FirstOrDefault(page => page.Text == playListName.Text)
?.Controls.Cast<Control>()
.FirstOrDefault(control => control is ListBox) as ListBox)?.Items.Add(songList.SelectedItem);
I have a form with a button and a tabcontrol. If I click on the button, it adds a new tab with a listbox inside the richtextbox of the tabcontrol, but once I move through the tabs, the listbox is only visibile/available on the newest tab and not in the previous tabs. Anyway ideas on how to fix this please? Below is my code:
private void button1_Click(object sender, EventArgs e)
{
if (tabControl1.Visible == false)
{
tabControl1.Visible = true;
listBox1.Visible = true;
}
TabPage tp = new TabPage();
RichTextBox rtb = new RichTextBox();
int tc = (tabControl1.TabCount + 1);
rtb.Controls.Add(listBox1);
tp.Text = "New " + tc.ToString();
tabControl1.TabPages.Add(tp);
rtb.Dock = DockStyle.Fill;
tp.Controls.Add(rtb);
return;
}
Your code is adding the same listbox to the new richtextbox you are creating; when the last added richtextbox is hidden (by moving to a different tab), the listbox is also hidden. You have two options:
Create a listbox for each richtextbox
Handle the selection change for the tab control and reattach the listbox to the currently visible richtextbox.
So, my problem is that i have a button in one form that needs to add a label in other form, label has a text that is from main labels textbox, and label has a backcolor that is from color block selected from main form.
private void btnAdd_Click(object sender, EventArgs e)
{
PiezimesLogs log = new PiezimesLogs();//form where the label would be added
Label l = new Label();// creates new label
l.Text = piezimeTxt.Text;
l.BackColor = ColorChange.BackColor;
log.Controls.Add(l);
}
so, this is the code from button that should do everything.
log - other form in which the label should be created.
c# win form
Instead of creating a new label, you could simply add an empty label to your 'target-form'.
Afterwards, you can simply modify the labels' text in order to make it appear.
Regards,
Michael
How do I create a control in a windows form application? I want to generate a textbox or a radio button when I select something from a Combobox. I basically want to query my database, and based on the values of the fields, I want to generate a textbox or a radio button. For example, if my query returns a value of "Textbox", I want to generate a textbox on the form in a specified location. How does one accomplish this? Please help.
The easiest way is to create the control manually in code and then add it to the Controls collection. Deciding which control to create depending on some input data (whether it's database query or a value selected from a combobox) is not much different then in any other case. Simple if will do the job. For instance:
private void AddControl(string control)
{
if (control == "Textbox")
{
TextBox tb = new TextBox();
tb.Location = new Point(100, 100);
this.Controls.Add(tb);
}
else if (control == "Radio")
{
RadioButton rb = new RadioButton();
rb.Location = new Point(200, 100);
this.Controls.Add(rb);
}
}
Of course, it's very naive version. But it's only a starting point. I leave to you adding more advanced logic (like dynamically adjusting location, setting up properties of the radio button or the textbox, relying on Type instead of on a simple string, etc.)
The assumption is that you retrieve a string value from the database. For example in form's constructor:
public Form1()
{
InitializeComponent();
string requestedControl = QueryDatabase();
AddControl(requestedControl);
}
I leave to you implementing the method to query the database.
In the question you also mentioned adding a control after selecting it in the combobox. In this case the only difference is that you rely on an event triggered after combobox's selection changed:
private void comboBox1_SelectedValueChanged(object sender, EventArgs e)
{
string res = this.comboBox1.SelectedItem.ToString();
this.AddControl(res);
}
Here you rely on SelectedValueChanged event. Of course, in this case your combobox has to be populated with expected values (here "Radio" and "Textbox"). Also, you have to attach the event handler to the specific event on the combobox. You can do that in designer or by adding in the constructor the following line:
combobox1.SelectedValueChanged += comboBox1_SelectedValueChanged;
Hope that clarifies the issue and sets up some starting point for you to continue from.