how to pass variable value in event handler

viva

Hi

I am beginner in C#.
In for loop , I am creating panel control with Image inside (calling 10 images),When I click on image , it should display value of that Image (Image number) using pop up message box. Please suggest code for the same

public Form1()
        {
            InitializeComponent();
            System.ComponentModel.ComponentResourceManager resources = new System.ComponentModel.ComponentResourceManager(typeof(Form1));

            for (int count = 1; count < 11; count++)
            {
                 this.panel1 = new System.Windows.Forms.Panel();

                // panel1
                this.panel1.BackgroundImage = Image.FromFile(Application.StartupPath + "\\activecell.jpg");
                this.panel1.BackgroundImageLayout = System.Windows.Forms.ImageLayout.Center;
                this.panel1.Location = new System.Drawing.Point(50, 50);
                this.panel1.Name = "panel1" + count;
                this.panel1.Size = new System.Drawing.Size(70, 35);
                this.panel1.Click += new System.EventHandler(this.panel1_Click);

                this.flowLayoutPanel1.Controls.Add(this.panel1);

            }

        }
private void panel1_Click(object sender, EventArgs e)
        {

        }

as I can not pass count variable to panel1_Click variable and i want to display count value on message box.

please reply

regards
Viva

8 Replies

Know the answer? Post it — somebody with the same question will find it here.

Vulpes13y ago
Accepted answer
If you want to pass any variable at all to the handler then you can set the panel's Tag property which is of type object and so an accept a value of any type:

public Form1()
{
InitializeComponent();
System.ComponentModel.ComponentResourceManager resources = new System.ComponentModel.ComponentResourceManager(typeof(Form1));

for (int count = 1; count < 11; count++)
{
this.panel1 = new System.Windows.Forms.Panel();
this.panel1.Name = "Image" + count.ToString();
this.panel1.Tag = "whatever";
// panel1
this.panel1.BackgroundImage = Image.FromFile(Application.StartupPath + "\\activecell.jpg");
this.panel1.BackgroundImageLayout = System.Windows.Forms.ImageLayout.Center;
this.panel1.Location = new System.Drawing.Point(50, 50);
this.panel1.Name = "panel1" + count;
this.panel1.Size = new System.Drawing.Size(70, 35);
this.panel1.Click += new System.EventHandler(this.panel1_Click);

this.flowLayoutPanel1.Controls.Add(this.panel1);

}

}

private void panel1_Click(object sender, EventArgs e)
{
Panel p = (Panel)sender;
string number = p.Name.Substring(5);
string tag = p.Tag.ToString();
MessageBox.Show("Image " + number + " clicked with tag " + tag);
}
0
viva13y ago
Thank u very much for your quick reply.

It is working
0
Vulpes13y ago
If you know that the Tag property will contain an integer, then you can cast it to one before doing any arithmetic or arithmetic comparisons:

Panel p = (Panel)sender;
string number = p.Name.Substring(5);
int tag = (int)p.Tag;
if (tag < 10)
MessageBox.Show("Image " + number + " is active");
else
MessageBox.Show("Image " + number + " is disabled");
0
viva13y ago
but now in the same event, I want to compare to display different messages.

Panel p = (Panel)sender;
            string number = p.Name.Substring(5);
            string tag = p.Tag.ToString();
            if (tag<10)
            MessageBox.Show("Image " + number + " is active");
            else

                MessageBox.Show("Image " + number + " is disable");

but for red mark code I am getting error as

operator can not be applied to operands of type string to int
0
viva13y ago
ok I got it by doing

this.panel1.Tag = count;

thank u very much
0
viva13y ago
by doing this i am getting "count" as string.But i want the value of that count??
0
viva13y ago
Hi Thanks for the reply. It is working.

But I want to pass any variable value declare in public Form1() to that event.How to do that?

suppose there is other for loop inside running and want to pass that value.how to pass integer??

Viva
0
Vulpes13y ago
Try this:

public Form1()
{
InitializeComponent();
System.ComponentModel.ComponentResourceManager resources = new System.ComponentModel.ComponentResourceManager(typeof(Form1));

for (int count = 1; count < 11; count++)
{
this.panel1 = new System.Windows.Forms.Panel();
this.panel1.Name = "Image" + count.ToString();
// panel1
this.panel1.BackgroundImage = Image.FromFile(Application.StartupPath + "\\activecell.jpg");
this.panel1.BackgroundImageLayout = System.Windows.Forms.ImageLayout.Center;
this.panel1.Location = new System.Drawing.Point(50, 50);
this.panel1.Name = "panel1" + count;
this.panel1.Size = new System.Drawing.Size(70, 35);
this.panel1.Click += new System.EventHandler(this.panel1_Click);

this.flowLayoutPanel1.Controls.Add(this.panel1);

}

}

private void panel1_Click(object sender, EventArgs e)
{
Panel p = (Panel)sender;
string number = p.Name.Substring(5);
MessageBox.Show("Image " + number + " clicked");
}
0