Dynamically created button in asp.net and c#

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Hi,
I am creating online examination project in asp.net & c#.
I want to display buttons for each question at the bottom of my .aspx web page, so that whenever student clicks button, question for that button will be displayed.
I am creating buttons dynamically as :

C#

void CreateButtons()
{
    for (int i = 1; i < 70; i++)
    {

        Button btn = new Button();
        btn.Text = i.ToString();

        btn.Font.Bold = true;
        btn.ForeColor = System.Drawing.Color.Black; ;
        btn.BackColor = System.Drawing.Color.LightSkyBlue;
        btn.Font.Size = 10;
        btn.Width = Unit.Pixel(50);
        pnlButtons.Controls.Add(btn);
        pnlButtons.Visible = true;
        btn.Click += new EventHandler(btn_Click);

    }
}

and getting the questions in

C#

void btn_Click(object sender, EventArgs e)
{
}

Now i want to change color of each button as soon as answer is selected in radiobutton list.
On selectedindex of radiobutton list, i m not able to access dynamically created buttons.

Can anyone let me know how to change colour of Dynamically created button on radiobuttonlist selected event.

[edit]Code block added - OriginalGriff[/edit]

Posted 9-Sep-11 19:18pm

akkanshagupta

Updated 9-Sep-11 19:26pm

OriginalGriff

v2

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OriginalGriff · Answer 1 · 2011-09-09T19:51:00

It's a little complicated, but not too bad:
1) Add this line to your CreateButtons method:

C#

btn.Width = Unit.Pixel(50);
btn.ID = string.Format("butDynamic{0}", i);    // Give the button a unique ID
pnlButtons.Controls.Add(btn);

2) Add a Hidden field to your Page:

ASP.NET

<asp:HiddenField ID="PressedButton" runat="server" />

3) Add this code to your Button handler:

C#

void btn_Click(object sender, EventArgs e)
    {
    Button b = sender as Button;
    if (b != null)
        {
        // Save the last pressed ID for later
        PressedButton.Value = b.ID;
        }
    }

4) Add this code to your SelectedIndexChanged event:

C#

if (PressedButton.Value != null)
    {
    Button b = (Button) (pnlButtons.FindControl((string) PressedButton.Value));
    if (b != null)
        {
        b.BackColor = System.Drawing.Color.Red;
        }
    }

Do bear in mind that you only get the Selected Index changed event when the RadioListBox loses the focus - NOT when the user makes a selection.

kranthi.oru · Answer 2 · 2011-09-10T00:06:00

Solution 4

If u got answer please mark up

Posted 10-Sep-11 0:06am

kranthi.oru

Mario Majčica · Answer 3 · 2011-09-09T20:02:00

The problem is in the event handler.

Try this code:

private void button1_Click(object sender, EventArgs e)
{
    int distance = 0;
    EventHandler evh = new EventHandler(btn_Click);

    for (int i = 0; i < 5; i++)
    {
        Button btn = new Button();
        btn.Text = i.ToString();

        btn.ForeColor = System.Drawing.Color.Black; ;
        btn.BackColor = System.Drawing.Color.LightSkyBlue;
        btn.Width = 50;
        btn.Location = new Point(distance, 0);
        distance = distance + 50;
        this.Controls.Add(btn);
        btn.Click += evh;
    }

}

void btn_Click(object sender, EventArgs e)
{
    string a = string.Empty;
}

Cheers

Dynamically created button in asp.net and c#

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