ASP.NET FindControl memory leak - asp.net

Question

we have discover recently that our ASP.NET application has a lot of lines like this:
Label lbXXX = (Label)FormView.FindControl("lbXXX");
same for TextBox, Panel, Image, DropDownList...
Could this be the reason of a memory leak?
Is as bad as I think?

Answer 1

This is not likely to be causing a memroy leak.
To find the cause of a memory leak you should be using a memory profiler and find out what is holding on to references that it shouldn't be.
The most common reason for memory leaks in .NET is event handlers that have not been unregistered, though this tends to not be a problem in ASP.NET due to its request per thread model.
If you suspect a memory leak (how have you determined that you do have one?), profile in order to find the reason - don't assume.

Answer 2

Memory leaks, impossible here. yeah excessive use of find control is not recommended. Since you observing lot of such incidents then better resolve them and clean your code. Performance is also hitting currently due find control.

Answer 3

It's unlikely that it causes memory issues. However, it doesn't come without cost.
As you can see below, the first action is EnsureChildControls which calls CreateChildControls if they are not created yet. That might cause your performance/memory issue.
Called by the ASP.NET page framework to notify server controls that
use composition-based implementation to create any child controls they
contain in preparation for posting back or rendering.
Then not FindControl would have this issue but your custom control(s).
This is the implementation (from ILSpy):
protected virtual Control FindControl(string id, int pathOffset)
{
this.EnsureChildControls();
if (!this.flags[128])
{
Control namingContainer = this.NamingContainer;
if (namingContainer != null)
{
return namingContainer.FindControl(id, pathOffset);
}
return null;
}
else
{
if (this.HasControls())
{
this.EnsureOccasionalFields();
if (this._occasionalFields.NamedControls == null)
{
this.EnsureNamedControlsTable();
}
}
if (this._occasionalFields == null || this._occasionalFields.NamedControls == null)
{
return null;
}
char[] anyOf = new char[]
{
'$',
':'
};
int num = id.IndexOfAny(anyOf, pathOffset);
string key;
if (num == -1)
{
key = id.Substring(pathOffset);
return this._occasionalFields.NamedControls[key] as Control;
}
key = id.Substring(pathOffset, num - pathOffset);
Control control = this._occasionalFields.NamedControls[key] as Control;
if (control == null)
{
return null;
}
return control.FindControl(id, num + 1);
}
}