c# - How to check first textbox value is in second textbox textmode -

i have 2 textboxes:

• textbox1
• textbox2

i want when first textbox have valid date second textbox's value become next week like:

if(textbox1.text== textbox2.textmode) {     txtdateto.text = datetime.parse(txtdatefrom.text, system.globalization.cultureinfo.invariantculture).adddays(7).tostring("mm/dd/yyyy"); } 

use textchanged event of txtdatefrom like:

private void txtdatefrom_textchanged(object sender, eventargs e) {     var styles = datetimestyles.none;     datetime datevalue;     if(datetime.tryparse(txtdatefrom.text, system.globalization.cultureinfo.invariantculture, styles, out datevalue))     {         textbox2.text = convert.tostring(datevalue.adddays(7));     }     else     {         textbox2.text = "invalid datetime inserted in txtdatefrom;";     } } 

make sure connect event correctly, example using designer @ event section of textbox.