I have made a user control with a pic box and a blank label. How do I expose the label so I can update the text value from my main .net application. I have not written any c# code in about 10 years, and was just thrown a project. All I have for code is:
namespace RHeader1
{
public partial class RHeader : UserControl
{
public RHeader()
{
InitializeComponent();
}
}
}
Please for give my stupidity. I know I need to do a get/set but?????
I presume you mean because controls are not public, the proper way to access them are via a property (which I agree with) - so you can just expose a property which updates the label directly - I'm presuming this is winforms
public string Label
{
get { return label1.Text; }
set { label1.Text = value; }
}
Use this:
Label lbl= (Label)myUserControl.FindName("yourlabelname");
This way you can find and update your label control settled in the UserControl.
You could change the Label's modifier property to public, this will result in the labels properties been visible from the UC's property window and also allow you to do something like
uc.label.Text = "foo";
if you haven't delclared the label:
label1 = new label();
then
label1.text = "some text";
where you can replace "Some text" with any string value.
Related
I`m trying to modify on job the Text of a label (label.Text) that I have previously added to a panel (MyPanel.Controls.Add(MyLabel).
I add the label to the panel in a function:
public PanelEx nameoffunction()
{
.
.
MyPanel.Controls.Add(MyLabel);
return MyPanel;
.
.
}
MyPanelWithControl = nameoffunction();
Now I have in MyPanelWithControl the panel with a label. How can I now access to the label previously added to modify one of its fields?
You can find a control using its Name property:
MyLabel.Name = "label1";
MyPanel.Controls.Add(MyLabel);
...
MyPanel.Controls["label1"].Text = "updated text";
However, this approach can lead to problems later if you make changes to your user interface. If you moved the label to another panel, or changed its name, then the code which tries to find it using the name would still compile but cause an error at runtime. For long-term projects it's preferable to store references to controls as properties:
public class PanelEx : Panel {
...
public Label MyLabel { get; set; }
}
public PanelEx nameoffunction() {
...
MyPanel.MyLabel = MyLabel;
return MyPanel;
}
And then you can access the Label directly from the panel object:
MyPanel.MyLabel.Text = "updated text";
Here I'm talking about Windows Forms Application written in C#. Consider a simple model
class Labelled
{
private string label;
public string Label
{
get { return label; }
set
{
if (label != value)
{
string message = String.Format(
"Label changed from {0} to {1}",
label, value
);
MessageBox.Show(message);
label = value;
}
}
}
public Labelled(string label)
{
this.label = label;
}
}
class Model
{
public Labelled SingularLabelled { get; set; }
public List<Labelled> ListedLabelled { get; set; }
public Model()
{
SingularLabelled = new Labelled("Singular");
ListedLabelled = new List<Labelled>();
for (int i = 1; i <= 10; ++i)
ListedLabelled.Add(new Labelled("Listed " + i.ToString()));
}
}
We have a simple class Labelled with string property Label and class Model with member SingularLabelled of type Labelled and ListedLabelled which is a list of Labelled's.
Now I want to display the data to the user. Here is my setup:
The main window has a TextBox for displaying SingularLabelled.Label and a DataRepeater from the Visual Basic PowerPacks to display labels of the elements of ListedLabelled. The ItemTemplate of the DataRepeater consists of just a single TextBox.
Let's focus on one way binding, namely I want the underlying data to be updated when the User changes the contents of a text box. The Label property of the Labelled raises a notification in form of a message box, so I can get to know exactly when the data is being updated. Now the arrows represent bindings. Blue arrows stand for data source and the red ones for data members. An instance of Model is created and bound to the modelBindingSource in the constructor of the main window form.
And here we come to a very important thing. I want the data to be updated immediately in sync with what the User is typing, so I made sure that the data source update modes of the data bindings are set to OnPropertyChanged. The generated code that might be of interest here is
this.singularTextBox.DataBindings.Add(new System.Windows.Forms.Binding("Text", this.modelBindingSource, "SingularLabelled.Label", true, System.Windows.Forms.DataSourceUpdateMode.OnPropertyChanged));
this.listedTextBox.DataBindings.Add(new System.Windows.Forms.Binding("Text", this.listedLabelledBindingSource, "Label", true, System.Windows.Forms.DataSourceUpdateMode.OnPropertyChanged));
And this is working as expected when typing into the text box of SingularLabelled but the text boxes within DataRepeater trigger the update only when they loose focus. I want them to behave like the singular one. Ideal solution would be to do it using the designer. Does anyone know how to do this?
Above is a sample of the program working. Notice how SingularLabelled's label is updated every character put in and the members of ListedLabelled get the whole edited chunk updated after the corresponding text box looses focus.
We were able to overcome this limitation of DataRepeater by simulating the Tab key.
private void listedTextBox_TextChanged(object sender, EventArgs e)
{
//simulate tab key to force databinding
SendKeys.Send("{TAB}");
SendKeys.Send("+{TAB}");
}
Let's say I have a label in a custom control. In the constructor I set it's text value.
The label doesn't refresh. It does so only when in a client form.
How can I update this label on the custom control itself programmatically ?
Make the text of the label accessible as a property of the Control:
(The getter is not necessary for your case, so you can leave that out if you don't want it)
public string LabelText
{
get
{
return Label1.text;
}
set
{
Label1.text = value;
}
}
This way the property will even show up in the designer of the control, or you can set it programmatically lik this:
MyControl.LabelText = "text";
I have created a WindowsFormControlLibrary porject. It works fine, I can drop it on the forms,call its methods,etc ...
but now as a property of it, I am passing the name of a Label to it. and I want this custom control to be able to use that label name and for example change its font to bold .
so the question is that if I have a WinForm and I have a Label on that form and my custom control on that form, then how can I tell my custom control to do something with that label which I am passing its name to it?
Instead of sending in the name of the label, send in a reference to the actual label and then the custom control can both read the name if it needs to and change the label's font and other properties.
Be careful though, it can quickly get messy to keep track of what's happening if various forms and controls change controls on other forms etc.
Edit: Added code to do what you ask for in the comments
Code isn't tested so it might not be completely correct, but something similar to this should work.
foreach (Control c in Parent.Controls)
{
if (c is Label)
{
Label l = (Label)c;
// do stuff to label l
}
}
First, if you wish to access a Control from your UserControl, you will need to use the FindForm() method.
Second, you will be required to expose your TextBox control, for example, through a property of your form.
Then, you would need to know the type of this Form returned by this FindForm() method.
Once you know it, you need to type-cast this result to the correct type.
So, here a sample untested pseudo-code to give you the idea:
public partial class MyMainForm {
private TextBox textBox1;
public MyMainForm() {
textBox1 = new Textbox();
textBox1.Name = #"textBox1";
textBox1.Location = new Point(10, 10);
textBox1.Size = new Size(150, 23);
this.Controls.Add(textBox1);
}
public Font MyTextBoxFont {
get {
return textBox1.Font;
} set {
if (value == null) return;
textbox1.Font = value;
}
}
}
Then, assuming you have dropped your control on your form, your UserControl could have a property like so:
public partial class MyUserControl {
private Form GetContainerForm {
get {
return this.FindForm();
}
}
// And later on, where you need to set your TextBox's font:
private void SetContainerInputFieldFont(Font f) {
if (GetContainerForm == null) return; // Or throw, depending on what you need to do.
((MyMainForm)GetContainerForm).MyTextBoxFont = f
}
}
cool :) I just added a get set public property of type Label... it automatically lists all the label on the form.
I've got a Windows Form User Control with a string property for setting the text of a textbox. This string can be multi-line.
I've noticed that on some controls with a text property, and instead of being forced to type in the single line property textbox, you get a little pop up where you can type multiple lines. (As a matter of fact, a Windows Forms Textbox control allows this on the Text property.)
How do I enable this functionality in the properties window for the property I have designed?
The following is not real code in my app, but an example of how such a property might be defined
public string Instructions
{
get
{
return TextBox1.Text;
}
set
{
TextBox1.Text = value;
}
}
You can use the EditorAttribute with a MultilineStringEditor:
[EditorAttribute(typeof(MultilineStringEditor),
typeof(System.Drawing.Design.UITypeEditor))]
public string Instructions
{
get
{
return TextBox1.Text;
}
set
{
TextBox1.Text = value;
}
}
To avoid adding a reference to System.Design and thus requiring the Full framework, you can also write the attribute like this:
[EditorAttribute(
"System.ComponentModel.Design.MultilineStringEditor, System.Design",
"System.Drawing.Design.UITypeEditor")]
Although this is less of a problem now that they've stopped splitting the framework into a Client Profile and a Full one.