Dynamically generating buttons in ASP.NET and passing values to Codebehind

Question

I'm using a foreach loop to generate content how do I listen for a button click to call codebehind function. I can't set a value for a ASP button. How should I go about this ? When the user clicks on a button I want the ID for the user they clicked on to get passed to codebehind

Answer 1

You can pass the ID in the CommandArgument property of a button and you can assign the onclick event all inside the loop:

//for loop
//...
Button btn = new Button();
//etc
btn.CommandArgument = theID;
btn.Click += new EventHandler(btn_Click);
//...
//end for loop

protected void btn_Click(object sender, EventArgs e)
{
    //Need to know which btn was clicked
    Button btn = sender as Button;
    if(btn == null)
    {
        //throw exception, etc
    }
    int id = Convert.ToInt32(btn.CommandArgument);
    //etc
}

Answer 2

You can use Runtime generated Button Id to pass values to it.

//Counter for Dynamic Buttons.
int DynamicButtonCount = 1;

//This event generates Dynamic Buttons.
private void btnGenerate_Click(object sender, EventArgs e)
{
    string name = "Dynamic Button_" + DynamicButtonCount;
    Button btnDynamicButton = new Button();
    btnDynamicButton.Name = name;
    btnDynamicButton.Text = name;
    btnDynamicButton.Id=  DynamicButtonCount; //Use this id value
    btnDynamicButton.Size = new System.Drawing.Size(200, 30);
    btnDynamicButton.Location = new System.Drawing.Point(40, DynamicButtonCount * 40);
    btnDynamicButton.Click += new EventHandler(this.btnDynamicButton_Click);
    Controls.Add(btnDynamicButton);
    DynamicButtonCount++;
}

//This event is triggered when a Dynamic Button is clicked.
protected void btnDynamicButton_Click(object sender, EventArgs e)
{
    Button dynamicButton = (sender as Button);
    MessageBox.Show("You clicked. " + dynamicButton.Name);
}