Remove control created at runtime - c#

I wrote some code to create an additional textbox during runtime. I'm using the metro framework, but this shouldn't matter for my question.
When you click a button, a textbox is being created by a private on_click event:
private void BtnAddButton_Click(object sender, EventArgs e)
{
MetroFramework.Controls.MetroTextBox Textbox2 = new MetroFramework.Controls.MetroTextBox
{
Location = new System.Drawing.Point(98, lblHandy.Location.Y - 30),
Name = "Textbox2",
Size = new System.Drawing.Size(75, 23),
TabIndex = 1
};
this.Controls.Add(Textbox2);
}
What I want to do now is to use the click event of another button, to remove the Textbox again. What I am not sure about is, if I have to remove just the controll or also the object itself. Furthermore I can neither access the Textbox2 Control nor the object from another place.
private void BtnRemoveTextbox2_Click(object sender, EventArgs e)
{
this.Controls.Remove(Textbox2);
}
This does not work, since the other form does not know about Textbox2. What would be the best way to achieve my goal? Do I have to make anything public and if so, how do I do that?

You have to find it first before you choose to remove it.
private void BtnRemoveTextbox2_Click(object sender, EventArgs e)
{
MetroFramework.Controls.MetroTextBox tbx = this.Controls.Find("Textbox2", true).FirstOrDefault() as MetroFramework.Controls.MetroTextBox;
if (tbx != null)
{
this.Controls.Remove(tbx);
}
}
Here, Textbox2 is the ID of your textbox. Please make sure you're setting the ID of your textbox control before adding it.

You need to find those controls using Controls.Find method and then remove and dispose them:
this.Controls.Find("Textbox2", false).Cast<Control>().ToList()
.ForEach(c =>
{
this.Controls.Remove(c);
c.Dispose();
});

Since the control was created in another form, the current form has no way of knowing it by its instance name.
To remove it, loop through all controls and look for its Name:
private void BtnRemoveTextbox2_Click(object sender, EventArgs e)
{
foreach (Control ctrl in this.Controls)
{
if (ctrl.Name == "Textbox2")
this.Controls.Remove(ctrl);
}
}

Related

Winform copy button text to textbox using universal method

So this is a fairly straightforward thing, and I am just curious if there is a better way to do it to save lines of code. For class we are making a teletype machine. Basically there is a textbox, and a series of buttons A-Z and 0-9. When you click the button it adds the corresponding letter/number to the textbox. When you click send, it adds the contents of the textbox to a label and resets the textbox. Everything works and it only took a few minutes to build. However there is a mess of redundant lines and I was curious if there is a way to clean up the code with a method.
This is my current code.
private void btn_A_Click(object sender, EventArgs e)
{
box_UserInput.Text = box_UserInput.Text + "A";
}
As you can see, it is very simplistic and straight forward. Click A, and "A" gets added to the textbox. However the Text property of the button is also just "A" and I want to know if there is a way to just copy the text property of that button and add it to the textbox string.
Something like this, except with a universal approach where instead of having to specify btn_A it just inherits which button to copy based on the button clicked. That way I can use the same line of code on every button.
private void btn_A_Click(object sender, EventArgs e)
{
box_UserInput.Text = box_UserInput.Text + btn_A.Text;
}
You can use this which is more universal as the Control class contains the Text property. Also, using the best practice $"".
private void btn_A_Click(object sender, EventArgs e)
{
box_UserInput.Text = $"{box_UserInput.Text}{((Control)sender).Text}";
}
You can also assign the same event to each button. Create an event, say addControlTextOnClick and assign the same event to each button.
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void addControlTextOnClick(object sender, EventArgs e)
{
box_UserInput.Text = $"{box_UserInput.Text}{((Control)sender).Text}";
}
}
You can even shorten this more using this C# construct:
private void addControlTextOnClick(object sender, EventArgs e) =>
box_UserInput.Text = $"{box_UserInput.Text}{((Control)sender).Text}";

Retrieve values that are outside the context

I dynamically create controls and I'd like to be able to use them outside of the context.
For example a dynamically created label :
i = 0;
while (readerBE.Read())
{
Label labelBE = new Label();
labelBE.Name = "labelBE" + i;
labelBE.Text = readerBE["codeArticleComposant"].ToString();
labelBE.Cursor = Cursors.Hand;
labelBE.Click += new EventHandler(this.labelBE_Click);
i++;
}
And when I try to use the OnClick event to retrieve a value like this :
private void labelBE_Click(object sender, EventArgs e)
{
Console.WriteLine(labelBE.Text);
}
labelBE does not exist in the current context.
You can cast the sender argument:
private void labelBE_Click(object sender, EventArgs e)
{
Label labelBE = (Label) sender;
Console.WriteLine(labelBE.Text);
}
But one thing, you have a while-loop and you always create this Label and you never add it to any container control (like GroupBox, Panel or Form). So you would never create multiple and either the while-loop is wrong and should be replaced with an if or you should add the labels to a collection or parent control (well, you should do that anyway).
You can use the sender object that generated the click :
private void labelBE_Click(object sender, EventArgs e)
{
Console.WriteLine(((Label)sender).Text);
}
However I suggest you read more about Variable scope.
Your problem is that you create a variable inside a method, so this variable is no more accessible once you leave it.

C# editable listview

Yesterday I try to implement a new listview that support sub-item edit, my solution is to show a textbox when double click the sub-item. The key code as following:
protected override void OnDoubleClick(EventArgs e)
{
Point pt = this.PointToClient(Cursor.Position);
ListViewItem curItem;
int subItemIndex = GetSubItemAt(pt.X, pt.Y, out curItem);
DoubleClickEventArgs args = new DoubleClickEventArgs(subItemIndex);
base.OnDoubleClick(args);
if (subItemIndex>=0 && !args.Cancel)
{
//StartEdit(...);
}
}
public void EndEdit(bool acceptChanges)
{
//validation
.................
.................
AfterSubItemEventArgs e = new AfterSubItemEventArgs(this.SelectedItems[0], m_editSubItemIndex, this.SelectedItems[0].SubItems[m_editSubItemIndex].Text, m_textbox.Text, false);
OnAfterSubItemEdit(e);
if (e.Cancel)
{
//....
}
else
{
//set new value
}
m_textbox.Visible = false;
m_editSubItemIndex = -1;
}
OnAfterSubItemEdit is a event that user can do some validations or other operations. I add a check in this method, if the new value exist, I will show a messagebox to user firstly, then hide the textbox. But now, the problem comes, when i move the mouse, the listview items can be selected, I don't how to solve this issue, I tried my best to find out the way, but failed. So, please help me!
Listview has a LabelEdit property; when you set it "true", then in an event handler you can call Listview.Items[x].BeginEdit(), and edit an item. As an example, you can handle ListView.DoubleClick event and call BeginEdit right there:
private void Form1_Load(object sender, System.EventArgs e)
{
listView1.LabelEdit = true;
}
private void listView1_DoubleClick(object sender, System.EventArgs e)
{
if(this.listView1.SelectedItems.Count==1)
{
this.listView1.SelectedItems[0].BeginEdit();
}
}
The problem is that your form still calls the DoubleClick event whether the value exists or not. Add appropriate condition before calling base DoubleClick in your code, i.e.:
if(!new value exists)
base.OnDoubleClick(args);

In the WinForms DevExpress XtraWizard control, how can one hide the back button?

I know that if I set the WizardStyle of an XtraWizard control to WizardAero, it will remove or hide the back button from the first page instead of simply disabling it, as can be seen here. I want the same behaviour, but I want to keep the WizardStyle as Wizard97.
Is this possible, and if so, how?
One way to do this would be to use the CustomizeCommandButtons event on the WizardControl.
private void wizardControl1_CustomizeCommandButtons(object sender, CustomizeCommandButtonsEventArgs e)
{
e.PrevButton.Visible = false;
}
If you only want to hide it on the first page
private void wizardControl1_CustomizeCommandButtons(object sender, CustomizeCommandButtonsEventArgs e)
{
if(wizardControl1.SelectedPageIndex == 0)
e.PrevButton.Visible = false;
}
It seems like it will reset the visibility each time (so you don't need to toggle it back on). Anyway, I think this is what you're looking for.
http://documentation.devexpress.com/#WindowsForms/DevExpressXtraWizardWizardControl_CustomizeCommandButtonstopic
You can also set your own fields to the wizard buttons and then use these anywhere in your code. This will, for example, allow you to hide/disable the "Next" button until all fields page have been completed.
private void NodeConfigurationWizardCustomizeCommandButtons(object sender, CustomizeCommandButtonsEventArgs e)
{
_nextButton = e.NextButton;}
private void GetRowsButtonClick(object sender, EventArgs e)
{
var rowList = ServiceClient.GetAvailableRows();
var rowsReturned = rowList.Count > 0;
_nextButton.Button.Enabled = rowsReturned ;}

Get the currently focused textbox in C#

I have two textboxes, and a button. When I press the button, I want to know where my current caret is (either of the two boxes). I need this to know where to insert a certain text. I tried textbox1.Focused; textbox1.enabled but neither worked. How should I implement this? Thanks
Keep in mind that when you click the button, your textboxes will no longer have focus. You'll want a method of keeping track of what was in focus before the button's click event.
Try something like this
public partial class Form1 : Form
{
private TextBox focusedTextbox = null;
public Form1()
{
InitializeComponent();
foreach (TextBox tb in this.Controls.OfType<TextBox>())
{
tb.Enter += textBox_Enter;
}
}
void textBox_Enter(object sender, EventArgs e)
{
focusedTextbox = (TextBox)sender;
}
private void button1_Click(object sender, EventArgs e)
{
if (focusedTextbox != null)
{
// put something in textbox
focusedTextbox.Text = DateTime.Now.ToString();
}
}
}
There's a very simple way to do this.
Your requirement is simple since you only have two textboxes.
You can assign a class-wide string variable that holds when textbox1_GotFocus() is invoked as well as textbox2_GotFocus().
So if that textbox GotFocus() is called you assign a value.
Then put a condition for the class-wide string variable in the button that if the class-wide variable has a value of thats kind, that textbox is populated whatever you want to put in the textbox.
It worked for me so I believe it should work on you.

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