Creating Dynamic ComboBox in C# - c#

I'm new to Visual Studio 2010 C# and I'm creating an application where the user will select the number of textboxes will be shown in a form. For example, if the user will select "2" automatically there will be 2 boxes will be shown in the form.
This is the screenshots that I want to create.

I guess what you need to know is dynamic creation of controls.
To do what you want here you need to:
Create a control
Add control to form
Set control location, size and anything else you need
It would go something like this:
Texbox texbox = new Textbox();
Controls.Add(textbox);
textbox.Top = 20;
textbox.Left = 200;
textbox.Width = 200;
textbox.Name = "textbox1";
So that there's something left for you to do, you should repeat steps above in a loop, and calculate location of each textbox so that they're not stacked up.

comboBox1_SelectedIndexChanged(object sender, EventArgs e)
{
int i = 0;
int y = 0;
while (i < int.Parse(comboBox1.SelectedItem.ToString()))
{
System.Windows.Forms.TextBox tt = new System.Windows.Forms.TextBox();
y = y + 30;
tt.Location = new System.Drawing.Point(0, y);
this.Controls.Add(tt);
i++;
}
}
Hope this helps

Related

Dynamic radiobuttons in a dynamic panel in C#

I'm trying to make dynamicly created radiobuttons in my dynamicly created panel, but I'm not recieving what I'm trying to accomplish.
Here is my code:
private void Form1_Load(object sender, EventArgs e)
{
//Creating 3 panels
int counTer = 3;
for (int x = 0; x <= counTer; x++)
{
Panel panel = new Panel();
panel.Name = "panel" + x;
panel.Location = new Point(10 * (5 * x), 10);
panel.Size = new Size(150, 275);
//panel.BackColor = Color.Black; <-- Only for checking if they exist
panel.Controls.Add(panel);
//Creating 10 RadioButtons
int hoeveelHeid = 10;
for (int i = 0; i <= hoeveelHeid; i++)
{
RadioButton iets= new RadioButton();
iets.Name = "Waarde" + i;
iets.Text = "Waarde " + i;
iets.Location = new Point(5, 20 * i);
panel.Controls.Add(iets);
}
}
}
I'm not recieving any panels nor radiobuttons, does anyone see the mistake i made?
Thanks.
You are trying to add the panel you created to it's OWN control collection:
panel.Controls.Add(panel);
which means add the panel to the panel.
To add the panel to the form use:
this.Controls.Add (panel);
or even just:
Controls.Add (panel);
As suggested by Sinatr, you have to add the panel to your form like that:
this.Controls.Add (panel);
Otherwise your panel does exist, but it's not on your form.
For anyone who wants to hate with the reason that I only want to gain reputation, this answer's marked as community wiki.

How to create many labels and textboxes dynamically depending on the value of an integer variable?

Is there any way to dynamically create and display 'n' Labels with 'n' corresponding Textboxs when we know value of 'n' after for example, clicking "Display" button.
Let me know if anything make you don't understand my question. Thank you!
I am working with VS C# Express 2010 Windows Form.
I would create a user control which holds a Label and a Text Box in it and simply create instances of that user control 'n' times. If you want to know a better way to do it and use properties to get access to the values of Label and Text Box from the user control, please let me know.
Simple way to do it would be:
int n = 4; // Or whatever value - n has to be global so that the event handler can access it
private void btnDisplay_Click(object sender, EventArgs e)
{
TextBox[] textBoxes = new TextBox[n];
Label[] labels = new Label[n];
for (int i = 0; i < n; i++)
{
textBoxes[i] = new TextBox();
// Here you can modify the value of the textbox which is at textBoxes[i]
labels[i] = new Label();
// Here you can modify the value of the label which is at labels[i]
}
// This adds the controls to the form (you will need to specify thier co-ordinates etc. first)
for (int i = 0; i < n; i++)
{
this.Controls.Add(textBoxes[i]);
this.Controls.Add(labels[i]);
}
}
The code above assumes that you have a button btnDisplay and it has a onClick event assigned to btnDisplay_Click event handler. You also need to know the value of n and need a way of figuring out where to place all controls. Controls should have a width and height specified as well.
To do it using a User Control simply do this.
Okay, first of all go and create a new user control and put a text box and label in it.
Lets say they are called txtSomeTextBox and lblSomeLabel. In the code behind add this code:
public string GetTextBoxValue()
{
return this.txtSomeTextBox.Text;
}
public string GetLabelValue()
{
return this.lblSomeLabel.Text;
}
public void SetTextBoxValue(string newText)
{
this.txtSomeTextBox.Text = newText;
}
public void SetLabelValue(string newText)
{
this.lblSomeLabel.Text = newText;
}
Now the code to generate the user control will look like this (MyUserControl is the name you have give to your user control):
private void btnDisplay_Click(object sender, EventArgs e)
{
MyUserControl[] controls = new MyUserControl[n];
for (int i = 0; i < n; i++)
{
controls[i] = new MyUserControl();
controls[i].setTextBoxValue("some value to display in text");
controls[i].setLabelValue("some value to display in label");
// Now if you write controls[i].getTextBoxValue() it will return "some value to display in text" and controls[i].getLabelValue() will return "some value to display in label". These value will also be displayed in the user control.
}
// This adds the controls to the form (you will need to specify thier co-ordinates etc. first)
for (int i = 0; i < n; i++)
{
this.Controls.Add(controls[i]);
}
}
Of course you can create more methods in the usercontrol to access properties and set them. Or simply if you have to access a lot, just put in these two variables and you can access the textbox and label directly:
public TextBox myTextBox;
public Label myLabel;
In the constructor of the user control do this:
myTextBox = this.txtSomeTextBox;
myLabel = this.lblSomeLabel;
Then in your program if you want to modify the text value of either just do this.
control[i].myTextBox.Text = "some random text"; // Same applies to myLabel
Hope it helped :)
Here is a simple example that should let you keep going add somethink that would act as a placeholder to your winform can be TableLayoutPanel
and then just add controls to it
for ( int i = 0; i < COUNT; i++ ) {
Label lblTitle = new Label();
lblTitle.Text = i+"Your Text";
youlayOut.Controls.Add( lblTitle, 0, i );
TextBox txtValue = new TextBox();
youlayOut.Controls.Add( txtValue, 2, i );
}
Suppose you have a button that when pressed sets n to 5, you could then generate labels and textboxes on your form like so.
var n = 5;
for (int i = 0; i < n; i++)
{
//Create label
Label label = new Label();
label.Text = String.Format("Label {0}", i);
//Position label on screen
label.Left = 10;
label.Top = (i + 1) * 20;
//Create textbox
TextBox textBox = new TextBox();
//Position textbox on screen
textBox.Left = 120;
textBox.Top = (i + 1) * 20;
//Add controls to form
this.Controls.Add(label);
this.Controls.Add(textBox);
}
This will not only add them to the form but position them decently as well.
You can try this:
int cleft = 1;
intaleft = 1;
private void button2_Click(object sender, EventArgs e)
{
TextBox txt = new TextBox();
this.Controls.Add(txt);
txt.Top = cleft * 40;
txt.Size = new Size(200, 16);
txt.Left = 150;
cleft = cleft + 1;
Label lbl = new Label();
this.Controls.Add(lbl);
lbl.Top = aleft * 40;
lbl.Size = new Size(100, 16);
lbl.ForeColor = Color.Blue;
lbl.Text = "BoxNo/CardNo";
lbl.Left = 70;
aleft = aleft + 1;
return;
}
private void btd_Click(object sender, EventArgs e)
{
//Here you Delete Text Box One By One(int ix for Text Box)
for (int ix = this.Controls.Count - 2; ix >= 0; ix--)
//Here you Delete Lable One By One(int ix for Lable)
for (int x = this.Controls.Count - 2; x >= 0; x--)
{
if (this.Controls[ix] is TextBox)
this.Controls[ix].Dispose();
if (this.Controls[x] is Label)
this.Controls[x].Dispose();
return;
}
}

Newly created label will not show GUI

I am having some issues making my label show up in the gui... any thoughts?
private void addNewExcerciseButton_Click(object sender, EventArgs e)
{
int y = 305;
int x= 61;
string tempExcercise = excerciseTextBox.Text;
excerciseTextBox.Clear();
Label[] excerciseLabels = new Label[numExercises];
for (int i = 0; i < numExercises; ++i)
{
excerciseLabels[i] = new Label();
excerciseLabels[i].Text = ToString("{0}. {1}", i + 1, tempExcercise);;
excerciseLabels[i].Location = new System.Drawing.Point(x, y);
x += 10;
y += 10;
++numExercises;
}
}
thanks in advance.
numExercises is global.
You have to add each new Label to the collection of Controls contained by a visible Control (such as your Form). You're creating and setting them up, but they aren't part of the GUI yet until they're in the control hierarchy.
Add the following line after setting the location of the label:
this.Controls.Add(exerciseLabels[i]);
You need to add the label to the GUI:
this.Controls.Add(excersizeLabels[i]);
As a side note, there is no point in using an array.

Linking dynamically created text boxes and labels

I created an array of of TextBoxes and an array of Labels. When the information is updated in the TextBox I want it to change the Labels. How would I be able to do this? Below is piece of my code. I have not created the EvenHandler that I think is the part I need help with. All in C# using windows application form.
textBoxes = new TextBox[value];
labels = new Label[value];
for (int i = 1; i < value; i++)
{
textBoxes[i] = new TextBox();
textBoxes[i].Location = new Point(30, ToBox.Bottom + (i * 43));
labels[i] = new Label();
labels[i].Location = new Point(TopBox3[i].Width + 140, TopBox3[i].Top +3);
textboxes[i].ValueChanged += new EventHandler(this.TextBox_ValueChanged) ;
this.Controls.Add(labels[i]);
this.Controls.Add(textBoxes[i]);
}
You can remember the index of the TextBox in the Tag property
textBoxes[i].Tag = i;
and then use this value in your eventhandler to get the corresponding label (assuming that you hold the labels array as a local variable)
protected void TextBox_ValueChanged(object sender, EventArgs e)
{
TextBox textbox = sender as TextBox;
if(textbox==null)
return;
int index = Convert.ToInt32(textbox.Tag);
if(index >= 0 && index < this.labels.Length)
{
Label label = this.labels[index];
/* ... */
}
}
You should write something like this:
private void textBox1_ValueChanged(object sender, EventArgs e)
{
TextBox changedTxt = sender as TextBox;
for (int i = 1; i < value; i++)
if (textBoxes[i] == changedTxt)
{
Label lblToChange = labeld[i];
lblToChange.Text = changedTxt.Text;
break;
}
}
In the method the TextBox whose text has changed is passed as "sender". You look into your array for it, so you identify the index "i" which can be used to access the corresponding Label and to set its text.
BTW as Tim said, the event is TextChanged, not ValueChanged. Furthermore be aware that the event is triggered for every change in the text, i.e. as soon as you press a key the label will be updated. If you prefer to update your labels only when the user has finished to enter its text Leave is the event you should use.

Dynamic creation of control

for (int i = 0; i < 200; i++)
{
Control control = new Control();
control = new CheckBox();
Size size = control.Size;
Point point = new Point(20, 22);
control.Location = point;
int width = size.Width + 5;
i += width;
list.Add(control);
}
foreach(Control c in list)
{
}
how do I create a new instance of checkbox? Because this way I am getting just one checkbox each time. I want to get three checkbox in each row.
Is this winforms? A first point: you don't need the new Control() each time (you simly discard it anyway when you new CheckBox(). How exactly do you want the layout to appear? Can you describe it a bit more please?
I imagine TableLayoutPanel might be a reasonable start...
[STAThread]
static void Main() {
Application.EnableVisualStyles();
Form form = new Form();
TableLayoutPanel layout = new TableLayoutPanel();
layout.Dock = DockStyle.Fill;
form.Controls.Add(layout);
layout.AutoScroll = true;
layout.ColumnCount = 3;
// size the columns (choice just to show options, not to be pretty)
layout.ColumnStyles.Add(new ColumnStyle(SizeType.Absolute, 200));
layout.ColumnStyles.Add(new ColumnStyle(SizeType.Percent, 50));
layout.ColumnStyles.Add(new ColumnStyle(SizeType.AutoSize));
layout.GrowStyle = TableLayoutPanelGrowStyle.AddRows;
for (int i = 0; i < 200; i++)
{
CheckBox chk = new CheckBox();
chk.Text = "item " + i;
layout.Controls.Add(chk);
}
Application.Run(form);
}
Otherwise, you'll need to manually set the Location (or Top and Left) of each; not simple.
Your code has problems. Let's work from sample code rather than a lesson. I'll create a Panel first, nice if you want to remove the checkboxes you created. You'd probably be interested in the user clicking a checkbox so lets add an event for that. Start a new WF project and drop a button on the form. Double click it, then paste this code:
private void button1_Click(object sender, EventArgs e) {
// Give the 3 checkboxes a decent spacing
int height = this.Font.Height * 3 / 2;
// Create the panel first, add it to the form
Panel pnl = new Panel();
pnl.Size = new Size(100, 3 * height);
pnl.Location = new Point(10, 5);
this.Controls.Add(pnl);
// Make three checkboxes now
for (int ix = 0; ix < 3; ++ix) {
CheckBox box = new CheckBox();
box.Size = new Size(100, height);
// As pointed out, avoid overlapping them
box.Location = new Point(0, ix * height);
box.Text = "Option #" + (ix + 1).ToString();
box.Tag = ix;
// We want to know when the user checked it
box.CheckedChanged += new EventHandler(box_CheckedChanged);
// The panel is the container
pnl.Controls.Add(box);
}
}
void box_CheckedChanged(object sender, EventArgs e) {
// "sender" tells you which checkbox was checked
CheckBox box = sender as CheckBox;
// I used the Tag property to store contextual info, just the index here
int index = (int)box.Tag;
// Do something more interesting here...
if (box.Checked) {
MessageBox.Show(string.Format("You checked option #{0}", index + 1));
}
}
It looks like you get your 200 instances, all placed at the same point.
Instantiate 3 new checkboxes inside your loop body, set their properties accordingly and add each of them to the list. After the code above is complete, you will have 600 checkboxes.
list.Add(Control1);
list.Add(Control2);
list.Add(Control3);
I am not sure about what you are trying to do, but I cleaned up your code a bit:
for (int i = 0; i < 200; i++)
{
Control control = new CheckBox();
control.Location = new Point(20, 22);
i += control.Size.Width + 5;
list.Add(control);
}
You should not add a new instance to the list if you want to add the control you just made.
Also:
Control control = new Control();
control = new CheckBox();
Is a bit redundant. Also to not get one control at the same spot multiple times you should alter the point. Hope this helps

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