Loop through all textbox and dropdown controls on a webform and disable them

Question

Having some trouble with this one. I want to loop through every textbox and dropdown control on a webform and disable them under cerrtain conditions. I'm finding a lot of sample code for winforms, but apparently in a webform you can't use Control.Enabled because it doesn't exist. I've got this, which (again) doesn't work because I'm using a webform:

private void DisableControls(Control con) 
{
    foreach (Control c in con.Controls) 
    {
        DisableControls(c);
    }
    con.Enabled = false;
}

private void EnableControls(Control con)
{
    if (con != null)
    {
        con.Enabled = true;
        EnableControls(con.Parent);
    }
}

and I would call them in my Page_Load event like so:

 protected void Page_Load(object sender, EventArgs e) 
    {
        // If certain conditions exist, then...
        DisableControls(this);
        EnableControls(Button1);
    }

Answer 1

Why you are using recursion ? I don't understand that part.

You can make your method generic

private void DisableControls<T>(IEnumerable<T> controls) where T: Control
{
    foreach(var control in controls)
    {
        control.Enabled = false;
    }
}

Then call it:

DisableControls(this.Controls.OfType<TextBox>());
DisableControls(this.Controls.OfType<ComboBox>());

Answer 2

You could implement a walker:

public void ApplyToAllControls(Control node, Action<Control> lambda)
{
   lambda(node);

   foreach(Control c in node.Controls)
   {
       ApplyToAllControls(c, lambda);
   }
}

And implement two lambdas like this:

private void ControlDisabler(Control c)
{
    if(c != Button1)
    {
        c.Enabled = false;
    }
}

private void ControlEnabler(Control c)
{
    if(c != Button1)
    {
        c.Enabled = true;
    }
}

You then invoke them this way:

ApplyToAllControls(root, ControlDisabler);
ApplyToAllControls(root, ControlEnabler);

There are surely some rough edges you can smooth out but you should already get the basic idea.

With currying you can even parameterize the lambdas but that's a bit far to go.

Answer 3

private void DisableControls() 
{
    var Controls = this.Controls.OfType<TextBox>();
    foreach (Control c in Controls) 
    {
       ((TextBox)c).Enabled = false;
    }

}

private void EnableControls()
{
    var Controls = this.Controls.OfType<TextBox>();
    foreach (Control c in Controls) 
    {
       ((TextBox)c).Enabled = true;

    }
}

Answer 4

fastest solution you can use is change the

private void DisableControls(Control con)

to:

private void DisableControls(WebControl con)

that should work, of course do the same in the loop....

and now the explanations, the class Control doesn't have a definition for Enabled it is defined in an upper level base class ( WebControl ), so this is why you need to use it to gain access to enabled .

EDIT:

just checked the code and it fails on the literal control that is new line ( it inherits directly from control )

so the only other thing you need to add is something like this:

foreach (WebControl con in form1.Controls.OfType<WebControl>())
        {
            con.Enabled = false;
        }