Why ternary operator showing error ?

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dr[columnname] = datavalue.Trim() == "" ? DBNull.Value : Convert.ToInt32(datavalue);

what is the correct coding?

if datavalue.Trim() == "" then i want to pass the blank space to my column dr[columnname].

Posted 22-Jun-12 3:32am

Kamalkant(kk)

Updated 22-Jun-12 3:54am

v4

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Rajeev Jayaram 22-Jun-12 9:41am

Can you share the error message?

Kamalkant(kk) 22-Jun-12 9:54am

Type of conditional expression cannot be determined because there is no implicit conversion between 'System.DBNull' and 'int'

Rajeev Jayaram 22-Jun-12 10:01am

Keep your second and third operand the same type. Or explicitly cast it. See my answer, if that helps.

Clifford Nelson 22-Jun-12 13:11pm

Have any of these answers helped. I would like to know the answer, so please mark as answered any that help.

Kamalkant(kk) 25-Jun-12 4:14am

Hi Nelson Still I am not getting correct answer from any body.Can u plz give your Email_ID of gmail or any Contact Num.
My Email_ID is:kamalakanta.nayak09@gmail.com

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kishhr · Answer 1 · 2012-06-22T07:53:00

You are tring impossible:

See the below code:

XML

DataTable table = new DataTable();
            Nullable<int> X = 10;
            X = null;
            table.Columns.Add("Dosage", X.GetType() );
            string datavalue = "123";
            DataRow row = table.NewRow();
            row["Dosage"] = datavalue.Trim() == "" ? 0 : Convert.ToInt32(datavalue);

In this instead of 0, if you try null or DBNull or anything your application will not work, you should considering 0 instead

Richard MacCutchan · Answer 2 · 2012-06-22T03:42:00

Solution 1

You are mixing types in your expression, DBNull.Value[^] is not an Int32.

Posted 22-Jun-12 3:42am

Richard MacCutchan

Rajeev Jayaram · Answer 3 · 2012-06-22T03:57:00

Solution 4

Try this,

dr[columnname] = datavalue.Trim() == "" ? String.Empty : Convert.ToInt32(datavalue).ToString();

Or

dr[columnname] = datavalue.Trim() == "" ? (int?)null : Convert.ToInt32(datavalue);

Posted 22-Jun-12 3:57am

Rajeev Jayaram

Updated 22-Jun-12 4:34am

v2

Comments

Kamalkant(kk) 22-Jun-12 10:09am

my datavalue is integer type no need to convert it into string type

Rajeev Jayaram 22-Jun-12 10:29am

In that case try this,

dr[columnname] = datavalue.Trim() == "" ? (int?)null : Convert.ToInt32(datavalue);

Kamalkant(kk) 22-Jun-12 10:14am

Showing error as follows;

Input string was not in a correct format.Couldn't store <> in quantity Column. Expected type is Int32.

Rajeev Jayaram 22-Jun-12 10:32am

The bottomline is, you should tell the compiler what is the return type. It gets confused if both the operands are of different type. Try explicit casting in any one of the operands atleast.

kishhr · Answer 4 · 2012-06-22T03:46:00

Solution 2

You can pass null,

add dr[columnname] = datavalue.Trim() == "" ? null : Convert.ToInt32(datavalue);

Posted 22-Jun-12 3:46am

kishhr

Comments

phil.o 22-Jun-12 10:56am

False. There is no implicit conversion between null and Int32.
Your statement would return the same error message as OP's one.

Why ternary operator showing error ?

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