CODEWITHSUNDEEP
c#.net
David Zemina
David Zemina

Reputation: 171

Access specific properties of an object contained within a List<Object> in C#

I can't seem to figure out how to access specific properties of each object contained within a list. For example, if I reference the object outside of the list (prior to passing it to the button click), I can see properties like "tag", "height", "width", etc. (all the standard properties for that type). However, I cannot figure out how to access those object-specific properties once the list has been passed to my button click event.

Please refer to this example:

private TextBox createTextBox(string name)
{
    // Create TextBox Code is Here
    TextBox dTextBox = new TextBox();
    dTextBox.Name = name;
    dTextBox.Tag = "sometag";
    dTextBox.Height = 12345;
    dTextBox.Width = 12345;
    return dTextBox;
}

private void some_function()
{
    var objectList = new List<Object>();
    objectList.Add(createTextBox("example1"));
    objectList.Add(createTextBox("example2"));
    objectList.Add(createTextBox("example3"));
}

private int button_click(object sender, EventArgs e, Int32 ticketGroupID, List<Object> objectList)
{
    for(int i = 0; i < objectList.Count(); i++)
    {
        Int32 valuableInfo = objectList[i].?? // Here is where I am trying to access specific properties about the object at index i in the list, such as the objects TAG, VALUE, etc. How can this be done?
        // do things with the valuable info
    };

}

Thanks in advance for any assistance.

Upvotes: 1

Views: 70

Answers (3)

Kien Chu
Kien Chu

Reputation: 4895

You can either check type first, then cast it to TextBox later or reverse.

See example below: 

foreach (var obj in objectList)
{
    // method 1: check first, cast later
    if (obj is TextBox)
    {
        Int32 valueableInfo = ((TextBox)obj).Height;
    }

    // method2: cast first, check later
    var textBox = obj as TextBox;
    if (obj != null)
    {
        Int32 valueableInfo = obj.Height;
    }
}

Upvotes: 0

slugster
slugster

Reputation: 49974

It's a List<> which implements IEnumerable<T>, so you can make use of the OfType<T>() method to extract items that are already strongly typed and ready for you to access:

var myListOfTypedObjects = myList.OfType<TextBox>();
myListOfTypedObjects.ForEach(tb => Console.Writeline(tb.Name));

Upvotes: 1

Ian
Ian

Reputation: 30813

You need to make the object strongly-typed. That is, to cast it to your class:

Int32 valuableInfo = ((TextBox)objectList[i]).Height; //now you can access your property

Otherwise, you cannot access the properties of the class because the compiler wouldn't know what is the actual type of the object. Also, your Intellisense will just deemed it as object, not your strongly-typed class (example: MyClass, or in your case, the class being TextBox)

Upvotes: 1

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