String builder and String Concat

Question

I have a piece of code that look follows this pattern ,

 var stringBuilder =new StringBuilder( string.Concat(" string", _variable, 
"another string" , _variable2 ... );

according to some logic do

stringBuilder.Append(" Some more strings");

I don't like The mismatch of using StringBuilder and string.Concat and I want a more elegant way of doing

What I thought was using StringBuilder.Append like so ,

StringBuilder.Append("string");
StringBuilder.Append(_variable);
StringBuilder.Append("another string");

Is there a better way then this approach ?

[StringBuilder.AppendFormat](https://msdn.microsoft.com/en-us/library/system.text.stringbuilder.appendformat%28v=vs.110%29.aspx?f=255&MSPPError=-2147217396) — 001, May 18 '16 at 17:01

score 2 · Accepted Answer · answered May 18 '16 at 17:45

Actually the StringBuilder is AFAIK the first BCL class that supports fluent syntax, so you can simply chain multiple Append / AppendLine / AppendFormat calls:

var stringBuilder = new StringBuilder()
    .Append(" string").Append(_variable)
    .Append("another string").Append(_variable2)
    .Append(...);

score 0 · Answer 2 · answered May 18 '16 at 16:56

0

In C# 6 you can use string interpolation:

var stringbuilder = new StringBuilder($"string{_variable}another string");

answered May 18 '16 at 16:56

Matt Rowland

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Or in < C# 6 you can use [string.Format](https://msdn.microsoft.com/en-us/library/system.string.format(v=vs.110).aspx). – Kenneth K. May 18 '16 at 17:00
@KennethK. yes but the question stated specifically about no liking the mismatch – Matt Rowland May 18 '16 at 17:01
Perhaps, but using `string.Format` at least cleans up the string literal to be one string rather than 3+ strings. – Kenneth K. May 18 '16 at 17:08

score 0 · Answer 3 · answered May 18 '16 at 17:00

StringBuilder is the proper way to do a lot of string concatenation. It is specifically made for that and is optimal from performance point of view, so if you want a lot of string operations, use it. Otherwise if it's one small operation you can follow Matt Rowland advise (if you have C# 6), though you won't need StringBuilder for that at all:

string result = $"string {_variable} another string"

If you don't have C# 6, you can do:

string result = string.Format("string {0} another string", _variable)

String builder and String Concat

3 Answers3