c# - Regex in PreviewTextInput: only decimals between 0.0 and 1.0 -

i'd have regex, allows digits between 0.0 , 1.0 in textbox.

but should in method previewtextinput (c#, wpf project)

so normal regex doesn't work

regex regex = new regex(@"^0|0.0|0\.[0-9]*|1\.0|1$"); 

i've found regex, allows decimals in previewtextinput method:

regex regex = new regex("^[.][0-9]+$|^[0-1.]*[.,]{0,1}[0-9]*$"); 

how can change regex accept decimals between 0-1?

thanks.

my method decimals:

private void tb_previewtextinput(object sender, textcompositioneventargs e)     {         regex regex = new regex("^[.][0-9]+$|^[0-1.]*[.,]{0,1}[0-9]*$");         e.handled = !regex.ismatch((sender textbox).text.insert((sender textbox).selectionstart, e.text));     } 

my method decimals between 0-1 (doesn't work):

        private void tb_surface_previewtextinput(object sender, textcompositioneventargs e)     {         regex regex = new regex(@"^(0?\.[0-9]+|1\.0)$");         e.handled = !regex.ismatch(e.text);        // e.handled = !regex.ismatch((sender textbox).text.insert((sender textbox).selectionstart, e.text));      } 

@"^(0(?:\.\d+)?|1(?:\.0+)?)$" 

0 , 1 can matched,if don't want match them,and must have digits after dot ,you can use

@"^(0\.\d+|1\.0+)$" 

the code below want,and need remove last dot when textbox lost focus,such str.trim('.')

private void tb_surface_previewtextinput(object sender, textcompositioneventargs e) {     var patten = @"^(0(\.\d*)?|1(\.0*)?)$";     regex regex = new regex(patten);     e.handled = !regex.ismatch(e.text);     // e.handled = !regex.ismatch((sender textbox).text.insert((sender textbox).selectionstart, e.text)); }