How to get String.Format not to parse {0}

Question

I am writing a code generation tool that frequently will have lines like

StringBuilder sp = new Stringbuilder();
sp.AppendFormat("        public {0}TextColumn()\n", className);
sp.AppendLine("        {"
sp.AppendLine("            Column = new DataGridViewTextBoxColumn();");
sp.AppendFormat("            Column.DataPropertyName = \"{0}\";\n", columnName);

However the issue I am having is when I run in to a line like this.

sp.AppendFormat("return String.Format(\"{0} = '{0}'\", cmbList.SelectedValue);", columnName);

I want the first {0} to turn in to whatever the value of columnName is but I want the seccond {0} to be left alone so the internal String.Format will process it correctly.

How do I do this?

By the way, are you aware of the T4 engine for code generation included in Visual Studio? — Dirk Vollmar, Jul 23 '10 at 15:57
@0xA3 No I am not, does it work with the rt.click "Run Custom Tool"? That is what I am writing the code generation stuff for. — Scott Chamberlain, Jul 23 '10 at 15:58
These http://www.codeproject.com/KB/dotnet/customtoolsexp.aspx are the custom tools I am referring to. — Scott Chamberlain, Jul 23 '10 at 16:00

score 13 · Accepted Answer · edited Jul 23 '10 at 15:54

13

Use double curly braces:

string result = string.Format("{{Ignored}} {{123}} {0}", 543);

edited Jul 23 '10 at 15:54

Noldorin

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answered Jul 23 '10 at 15:53

Florian Reischl

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score 7 · Answer 2 · answered Jul 23 '10 at 15:54

Curly braces can be escaped by using two curly brace characters. The documentation of string.Format states:

To specify a single literal brace character in format, specify two leading or trailing brace characters; that is, "{{" or "}}".

In your example that would be

sp.AppendFormat("return String.Format(\"{0} = '{{0}}'\",cmbList.SelectedValue);", 
    columnName);

score 3 · Answer 3 · answered Jul 23 '10 at 15:54

3

sp.AppendFormat("return String.Format(\"{0} = '{{0}}'\", cmbList.SelectedValue);", columnName);

answered Jul 23 '10 at 15:54

Matthew Flaschen

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score 3 · Answer 4 · answered Jul 23 '10 at 15:54

3

Use "{{0}}". This will result in the string "{0}"

answered Jul 23 '10 at 15:54

Martin Ingvar Kofoed Jensen

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score 1 · Answer 5 · answered Jul 23 '10 at 15:54

1

String.Format(\"{0} = '{{0}}'\",

answered Jul 23 '10 at 15:54

James Curran

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How to get String.Format not to parse {0}

5 Answers5

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