C# – How to disable all controls in ASP.NET page

asp.net-controlscwebforms

I have multiple dropdownlist in a page and would like to disable all if user selects a checkbox which reads disable all. So far I have this code and it is not working. Any suggestions?

foreach (Control c in this.Page.Controls)
{
    if (c is DropDownList)
        ((DropDownList)(c)).Enabled = false;
}

Best Answer

Each control has child controls, so you'd need to use recursion to reach them all:

protected void DisableControls(Control parent, bool State) {
    foreach(Control c in parent.Controls) {
        if (c is DropDownList) {
            ((DropDownList)(c)).Enabled = State;
        }

        DisableControls(c, State);
    }
}

Then call it like so:

protected void Event_Name(...) {
    DisableControls(Page,false); // use whatever top-most control has all the dropdowns or just the page control
} // divs, tables etc. can be called through adding runat="server" property

Original Answer

In .NET it's rather ugly (until 4 or above):

StatusEnum MyStatus = (StatusEnum) Enum.Parse(typeof(StatusEnum), "Active", true);

I tend to simplify this with:

public static T ParseEnum<T>(string value)
{
    return (T) Enum.Parse(typeof(T), value, true);
}

Then I can do:

StatusEnum MyStatus = EnumUtil.ParseEnum<StatusEnum>("Active");

One option suggested in the comments is to add an extension, which is simple enough:

public static T ToEnum<T>(this string value)
{
    return (T) Enum.Parse(typeof(T), value, true);
}

StatusEnum MyStatus = "Active".ToEnum<StatusEnum>();

Finally, you may want to have a default enum to use if the string cannot be parsed:

public static T ToEnum<T>(this string value, T defaultValue) 
{
    if (string.IsNullOrEmpty(value))
    {
        return defaultValue;
    }

    T result;
    return Enum.TryParse<T>(value, true, out result) ? result : defaultValue;
}

Which makes this the call:

StatusEnum MyStatus = "Active".ToEnum(StatusEnum.None);

However, I would be careful adding an extension method like this to string as (without namespace control) it will appear on all instances of string whether they hold an enum or not (so 1234.ToString().ToEnum(StatusEnum.None) would be valid but nonsensical) . It's often be best to avoid cluttering Microsoft's core classes with extra methods that only apply in very specific contexts unless your entire development team has a very good understanding of what those extensions do.

C# – How to cast int to enum

From an int:

YourEnum foo = (YourEnum)yourInt;

From a string:

YourEnum foo = (YourEnum) Enum.Parse(typeof(YourEnum), yourString);

// The foo.ToString().Contains(",") check is necessary for enumerations marked with an [Flags] attribute
if (!Enum.IsDefined(typeof(YourEnum), foo) && !foo.ToString().Contains(","))
{
    throw new InvalidOperationException($"{yourString} is not an underlying value of the YourEnum enumeration.")
}

Update:

From number you can also

YourEnum foo = (YourEnum)Enum.ToObject(typeof(YourEnum) , yourInt);

Best Answer

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C# – Convert a string to an enum in C#

Original Answer

C# – How to cast int to enum

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