Expression on two integer type columns of datatable

Question

I want to know how to write expression in data table to concatenate two integer type columns. Because when i try with '+' it adds the two integers.

Thanks in advance.

Thanks Marco. But can you please tell me how to convert the integers to string. Because the expression to be provided to data column is in string. So it will be helpful if you provide an example. — Prateek Deshpande, Apr 12 '12 at 07:32

score 3 · Accepted Answer · answered Apr 12 '12 at 07:42

If you want to set the expression of the result column. try this.

DataTable table = new DataTable();

table.Columns.Add("OrderCount",typeof(int));

table.Columns.Add("OrderPrice",typeof(int));

table.Rows.Add(new object[] { 1, 1 });

table.Rows.Add(new object[] { 2, 3 });

table.Rows.Add(new object[] { 4, 5 });

table.Columns.Add("Result", typeof(string));

table.Columns["Result"].Expression = "Convert(OrderCount, 'System.String') + OrderPrice";

yamen · Answer 2 · 2012-04-12T07:40:02.743

1

The example:

int a = 1;
int b = 2;

var asInt = a + b; // asInt is now 3
var asString = a.ToString() + b.ToString() // asString is now "12"
var asStringAlt = String.Format("{0}{1}", a, b); // alternate method as suggested

edited Apr 12 '12 at 07:40

answered Apr 12 '12 at 07:27

yamen

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Would be better to do a string.format, performance wise. So `var asString = string.Format("{0}{1}", a, b);`. No need for unnecessary string casting this way. – Jan_V Apr 12 '12 at 07:37
@Jan_V: Updated to show both methods. Not sure which is more performant though. – yamen Apr 12 '12 at 07:40
In a lot of books they tell string.Format() is the better one (in theory) to use, because of performance and memory issues. But as suggested in this post: http://stackoverflow.com/questions/296978/when-is-it-better-to-use-string-format-vs-string-concatenation It probably doesn't matter much. – Jan_V Apr 12 '12 at 07:58

Expression on two integer type columns of datatable

2 Answers2