I'm getting System.FormatException: Input string was not in a correct format when running this method.
The values of the fields:
arrayName = "requester"; fieldList = "\"name\" : \"shimshon\""; // "name" : "shimshon" public override string ToString() { var val = string.Format("\"{0}\" : { {1} }", arrayName, fieldList); return val; } the expect result of the method is
"requester" : { "name" : "shimshon" } What is wrong with this format?
I think you want:
var val = string.Format("\"{0}\" : {{ {1} }}", arrayName, fieldList); Note the doubled {{ and }} which is the escape sequence necessary to get braces literally into the output.
Try
var val = string.Format("\"{0}\" : {{ {1} }}", arrayName, fieldList); 
Change:
public override string ToString() { var val = string.Format("\"{0}\" : { {1} }", arrayName, fieldList); return val; } on:
public override string ToString() { var val = string.Format("\"{0}\" : {{ {1} }}", arrayName, fieldList); return val; } The way escaped braces are interpreted can lead to unexpected results. For example, consider the format item "{{{0:D}}}", which is intended to display an opening brace, a numeric value formatted as a decimal number, and a closing brace. However, the format item is actually interpreted in the following manner:
The first two opening braces ("{{") are escaped and yield one opening brace.
The next three characters ("{0:") are interpreted as the start of a format item.
The next character ("D") would be interpreted as the Decimal standard numeric format specifier, but the next two escaped braces ("}}") yield a single brace. Because the resulting string ("D}") is not a standard numeric format specifier, the resulting string is interpreted as a custom format string that means display the literal string "D}".
The last brace ("}") is interpreted as the end of the format item.
The final result that is displayed is the literal string, "{D}". The numeric value that was to be formatted is not displayed.
You have to escape the { and } chars that are not part of the format.
string.Format("\"{0}\" : {{ {1} }}",.....) See this MSDN page:
http://msdn.microsoft.com/en-us/library/txafckwd.aspx
Opening and closing braces are interpreted as starting and ending a format item. Consequently, you must use an escape sequence to display a literal opening brace or closing brace. Specify two opening braces ("{{") in the fixed text to display one opening brace ("{"), or two closing braces ("}}") to display one closing brace ("}"). Braces in a format item are interpreted sequentially in the order they are encountered. Interpreting nested braces is not supported.
You need to escape the curly brackets that you want to be curly brackets in your output by using double brackets:
public override string ToString() { var val = string.Format("\"{0}\" : {{ {1} }}", arrayName, fieldList); return val; } 