Format Input for SharePoint DateTime field

We can use SharePoint API as well as SharePoint List web reference to update List Items. Using API it is quite straight forward as we can directly assign a DateTime object against a DateTime field in SharePoint list. But with List web reference it is not that straight forward as we need to first convert the DateTime object into the SharePoint DateTime formatted string and then assign it to the specific field. Provided below are code samples written in C# to format an input as per SharePoint DateTime field.

/* -- Format for Date Only Field -- */       private static String ToSPDate(String strDt) {     if (strDt == String.Empty)         return strDt;     else         return (Convert.ToDateTime(strDt)).ToString("yyyy-MM-dd"); }     /* -- Format for DateTime Field -- */ private static String ToSPDateTime(String strDt) {     if (strDt == String.Empty)         return strDt;     else         return (Convert.ToDateTime(strDt)).ToString("yyyy-MM-ddTHH:mm:ssZ"); }     /* -- Build List WebReference CAML String -- */ String strCamlBuilder = "<Method ID='1' Cmd='Update'>"; strCamlBuilder += "<Field Name='ID'>1</Field>"; strCamlBuilder += "<Field Name='DateOnlyField'>" + ToSPDate(strDtInput) + "</Field>"; strCamlBuilder += "<Field Name='DateTimeField'>" + ToSPDateTime(strDtTmInput) + "</Field>"; strCamlBuilder += "</Method>";