I have two controls created on Form_Load, a button and a combobox. I also have an event for the button, but the event should be able to see the newly created combobox.
When I try to call the combobox by it's name it says that it doesn't exist in this context.
private void Form1_Load(object sender, EventArgs e)
{
Button przycisk = new Button();
przycisk.Name = "przycisk";
przycisk.Dock = DockStyle.Bottom;
przycisk.Text = "Wybierz";
ComboBox kombo = new ComboBox();
kombo.Name = "kombo";
kombo.Dock = DockStyle.Bottom;
kombo.Items.Add("Przycisk");
kombo.Items.Add("Etykeita");
kombo.Items.Add("Pole tekstowe");
Controls.Add(kombo);
Controls.Add(przycisk);
przycisk.Click += new EventHandler(przycisk_Click);
}
private void przycisk_Click(object sender, EventArgs e)
{
kombo.Items.Add("Panel"); //just an example
}
Is there a way to make this work?
Only controls which are in used in markup with runat="server" will be class variables on your page. They are actually defined in the designer file.
What you'll want to do is in the class add something like the following where you have a class variable, then assign kombo in your page-load function. Then, it will exist in your click event handler.
// kombo is now scoped for use throughout this class
ComboBox kombo = null;
private void Form1_Load(object sender, EventArgs e)
{
Button przycisk = new Button();
przycisk.Name = "przycisk";
przycisk.Dock = DockStyle.Bottom;
przycisk.Text = "Wybierz";
// Assign to our kombo instance
kombo = new ComboBox();
kombo.Name = "kombo";
kombo.Dock = DockStyle.Bottom;
kombo.Items.Add("Przycisk");
kombo.Items.Add("Etykeita");
kombo.Items.Add("Pole tekstowe");
Controls.Add(kombo);
Controls.Add(przycisk);
przycisk.Click += new EventHandler(przycisk_Click);
}
private void przycisk_Click(object sender, EventArgs e)
{
// Using the kombo we created in form load, which is still referenced
// in the class
kombo.Items.Add("Panel"); //just an example
}
You will have to use the FindControl() method to find the object first.
private void przycisk_Click(object sender, EventArgs e)
{
ComboBox kombo = (ComboBox)FindControl("kombo");
kombo.Items.Add("Panel");
}
Related
I'm new to C#. I thought I knew a bit of C# but clearly not.
As an example I'm using a very plain form with a button and a custom textbox. Clicking on the button should give me the content of the custom textbox, but I'm getting
Error CS0103 The name 'tb' does not exist in the current context
I have tried all possible options provided but with no luck.
When I use a static textbox (named tb) from the toolbox then it works without any errors. Below is my code:
public Form1()
{
InitializeComponent();
}
public void Form1_Load(object sender, EventArgs e)
{
TextBox tb = new TextBox();
tb.Dock = System.Windows.Forms.DockStyle.Fill;
tb.Location = new System.Drawing.Point(600, 430);
tb.Multiline = true;
panel2.Controls.Add(tb);
}
public void button1_Click(object sender, EventArgs e)
{
MessageBox.Show(tb.Text);
}
I have tried to search Google and Stack Overflow, but I'm not sure what to search for.
This is a problem of scope. You are declaring tb in your method, so outside the method it doesn't exist. You want to declare tb outside the method in the class itself:
TextBox tb;
public Form1()
{
InitializeComponent();
}
public void Form1_Load(object sender, EventArgs e)
{
tb = new TextBox();
tb.Dock = System.Windows.Forms.DockStyle.Fill;
tb.Location = new System.Drawing.Point(600, 430);
tb.Multiline = true;
panel2.Controls.Add(tb);
}
public void button1_Click(object sender, EventArgs e)
{
MessageBox.Show(tb.Text);
}
Your tb variable is defined in the context of Form_Load(). Then it is added to the panel, then it goes out of scope. You need to find another way to get access to your text box... for example by making it a member variable of the class.
I'm having trouble passing values entered in form2(citacao) to form1(principal).
Principal.cs (form1)
richEditControl1.Document.AppendText(citacao.valor_edit[0]);
Citacao.cs (form2)
public string[] valor_edit = new string[3];
private void simpleButton2_Click(object sender, EventArgs e)
{
valor_edit[0] = memoEdit1.Text;
valor_edit[1] = comboBox1.SelectedItem.ToString();
valor_edit[2] = textEdit1.Text;
}
But when I click the button nothing happens , the values are not inserted into the richedit I like it.
I already have this on form (Pass DataGrid to ComboBox)
Form1 (principal)
private void barButtonItem1_ItemClick(object sender, DevExpress.XtraBars.ItemClickEventArgs e)
{
citacao cita = new citacao(this);
cita.Show();
}
form2(citação)
public citacao(principal gridForm)
{
InitializeComponent();
frm1 = gridForm;
}
// LOAD ALL FONTS (Referencias);
private void citacao_Load(object sender, EventArgs e)
{
comboBox1.Items.Clear();
foreach (DataGridViewRow row in frm1.DataGridView1.Rows)
{
comboBox1.Items.Add(row.Cells[0].Value.ToString());
}
comboBox1.SelectedIndex = 0;
}
let's see whether I understood your situation :)
declare your variable in Form 1 as a class variable
private citacao cita;
then initialize it in the button press event
private void barButtonItem1_ItemClick(object sender, DevExpress.XtraBars.ItemClickEventArgs e)
{
cita = new citacao(this);
// subscribe to the closing event
cita.FormClosing += form_FormClosing;
cita.Show();
}
// when Form 2 will be closed you can execute your important line in the event
void form_FormClosing(object sender, FormClosingEventArgs e)
{
// BUT! you have to use the variable name!
richEditControl1.Document.AppendText(cita.valor_edit[0]);
}
EDIT:
Ok after looking at the entire code:
please remove the button3! and this entire code:
private void button3_Click(object sender, EventArgs e)
{
cita = new citacao(this);
richEditControl1.Document.AppendText(citacao.valor_edit); // this line is the problem!
}
The function AppendText probably needs a string as parameter and you give the entire array!
If you subscribe to the closing event in Form1 / principal and also implement
the event, your data will be transmitted automatically as soon as the Form 2 disappears from the screen :)
I've made a TextBox that retains what you type, and when you click the button associated it gives you a messagebox. When people want to click no, I want the button to change location so people cannot click it so they are forced to click yes. Can you help me? Here is the code:
{
MsgBox = new CustomMsgBox();
MsgBox.label1.Text = Text;
MsgBox.button1.Text = btnOK;
MsgBox.button2.Text = btnCancel;
MsgBox.Text = Caption;
result = DialogResult.No;
MsgBox.ShowDialog();
return result;
}
private void button2_Click(object sender, EventArgs e)
{
button2.Location = new Point(25, 25);
}
private void button2_MouseHover(object sender, EventArgs e)
{
button2.Location = new Point(+50, +50);
}
private void button2_MouseLeave(object sender, EventArgs e)
{
button2.Location = new Point(+100, +100);
}
You will need to create your own form and make it act like a messagebox. Instead of creating a MessageBox, you will instantiate your own form and so that you can handle the buttons on it.
I am trying to access my dynamically created TextBox in C#, inside an event handler of a Button.
void MainFormLoad(object sender, EventArgs e)
{
this.Width=600;
this.Height=400;
this.FormBorderStyle= FormBorderStyle.FixedDialog;
TextBox t=new TextBox();
this.Controls.Add(t);
t.Location = new Point(60,40);
Label Mylable=new Label();
this.Controls.Add(Mylable);
Mylable.Location=new Point(15,43);
Mylable.Text="string : ";
t.Width=200;
t.Name="MyText";
t.Refresh();
Button Myb=new Button();
Myb.Location=new Point(270,40);
this.Controls.Add(Myb);
Myb.Text="Reverse it!";
Myb.Name="Mybo";
Myb.Click += new EventHandler(this.Myb_Clicked);
this.Refresh();
}
void Myb_Clicked(object sender, EventArgs e) {
// HOW SHOULD I GAIN ACCESS to MyText.Text HERE
MessageBox.Show();
}
Give a name to your dynamic TextBox:
TextBox t=new TextBox();
t.Name = "MyTextBox";
this.Controls.Add(t);
And then:
void Myb_Clicked(object sender, EventArgs e) {
string text = this.Controls["MyTextBox"].Text;
}
Wrong answer: object sender is the TextBox. You can cast sender to textbox and use it.
A decent way would be to make your textbox a class level member. And then you have access to it. If not, link TextBox.Text to a string property and use that.
You could keep a reference to your TextBox in your class
publc class MyForm: Form
{
TextBox myBox = null; // class member
void MainFormLoad(object sender, EventArgs e)
{
this.Width=600;
this.Height=400;
this.FormBorderStyle= FormBorderStyle.FixedDialog;
TextBox t=new TextBox();
myBox = t; // keep it for future reference
// rest of your code
}
void Myb_Clicked(object sender, EventArgs e) {
if (myBox !=null)
{
myBox.Text= "Clicked!";
}
MessageBox.Show();
}
}
I’m trying to dynamically declare an ImageButton.
I declare it and assign an ID and Image to it as follows:
ImageButton btn = new ImageButton();
btn.ImageUrl = "img/Delete.png";
btn.ID = oa1[i] + "_" + i;
btn.OnClick = "someMethod";
But when I try to assign an OnClick handler for the button it throws the following exception:
System.Web.UI.WebControls.ImageButton.OnClick is inaccessible due to protection level
You couldn't assign a value to a method like that, even if it were accessible. You need to subscribe to the event:
btn.Click += ClickHandlingMethod;
Take a look at this answer, it is related with dynamic controls and events
As Jon commented you cannot add a string to the event, in this case you need to add a handler for the event:
protected void Page_Init(object sender, EventArgs e)
{
var i = new ImageButton();
i.Click += new ImageClickEventHandler(i_Click);
this.myPanel.Controls.Add(i);
}
void i_Click(object sender, ImageClickEventArgs e)
{
// do something
}
Alternativeley
protected void Page_Init(object sender, EventArgs e)
{
var i = new ImageButton();
i.Click += (source, args) =>
{
// do something
};
this.myPanel.Controls.Add(i);
}
An example:
private void CreateAButton()
{
var button = new ImageButton();
button.ImageUrl = "yourimage.png";
button.ID = "Button1";
button.Click += ButtonClick;
Page.Form.Controls.Add(button);
}
private void ButtonClick(object sender, ImageClickEventArgs e)
{
// Do stuff here
// ...
}
You can use this code (one significant change) :
private void CreateAButton()
{
var button = new ImageButton();
button.ImageUrl = "yourimage.png";
button.ID = "Button1";
button.PostBackUrl = "http://www.towi.lt";
Page.Form.Controls.Add(button);
}
Trick is in "PostBackUrl". If you write correct link it will redirects to it (as in example). In other cases this will add original server name, '/' and text you entered. For example 'xxx' will be turned to "http://yourservername/xxx". It is very useful, when you working with redirects to same ISS, but different sites and dynamically creating buttons for users.