The server-side HTML control in the template column prompts that the server tag format is incorrect.

When using the template column of the gridview, you sometimes need to use the following: < ASP: templatefield >
< Itemtemplate >
< Input ID = Ttchk Name = Ttchk Type = Checkbox Value = "<% # Eval (" Saleorderid ") % > "Onclick =" ontttablecheck (this) "runat =" server "/>
</ Itemtemplate >
</ ASP: templatefield >

when running the result, the system prompts that the server tag format of the ttchk control is incorrect. Where is the error?
the original problem is double quotation marks. It is correct to use single quotation marks for the value attribute value, or to use single quotation marks for the binding statement, or not to use double quotation marks. Comparison:
value =" <% # eval (" saleorderid ") % > " (NO)
value = '<% # eval (" saleorderid ") % '(optional)
value =< % # eval (" saleorderid") % (yes)