How to Create ASP.NET Controls Dynamically Within Dynamically Created Controls?

Dynamic Control Creation in ASP.NET

Dynamically creating controls allows for flexibility in web page design, enabling the addition or removal of elements during runtime. This article will address how to dynamically create ASP.NET controls within dynamically created ASP.NET controls.

The example provided revolves around creating a multi-level control structure, where a dynamically created button generates additional HTML and controls within a placeholder.

Implementation

1. Create a placeholder control (e.g., phHazard) to serve as the container for dynamically generated controls.
2. Create an event handler for the button click event.
3. Within the event handler, retrieve the current control count from view state and increment it.
4. Generate the desired HTML and create the controls programmatically.
5. Assign the controls to the appropriate placeholder using FindControl.
6. Increment the control count and update the view state to persist the changes across postbacks.

Here's a code snippet illustrating the recommended approach:

private void createHazard(int hazardCount, int placeholderID)
{
    // HTML and control creation logic for the hazard...

    // Assign controls to the placeholder
    FindControl("phHazard" + placeholderID).Controls.Add(literalControl);
    FindControl("phHazard" + placeholderID).Controls.Add(dropDownList);

    // ...
}

Command Argument

To send additional information when the button is clicked, you can use CommandArgument:

// Add argument to button
button.CommandArgument = "Create Hazard";

// Get argument in event handler
string buttonArgument = e.CommandArgument.ToString();

Troubleshooting

Remember, dynamically created controls will be lost upon postback unless manually recreated. Consider recreating these controls in the Page_Load event to prevent data loss.

The above is the detailed content of How to Create ASP.NET Controls Dynamically Within Dynamically Created Controls?. For more information, please follow other related articles on the PHP Chinese website!