object reference not set to an instance of an object(i got an error through the below code)

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DataTable dt = ds.Tables[0];


                HolidayReg objHoliday = new HolidayReg();

                for (int row = 0; row < dt.Rows.Count; row++)
                {
                    objHoliday = new HolidayReg();
                    foreach (DataColumn dc in dt.Columns)
                    {
                        foreach (PropertyInfo prop in objHoliday.GetType().GetProperties())
                        {

                            if (prop.Name == dc.ColumnName && prop.CanWrite)
                            {
                                if (dt.Rows[row][dc.ColumnName] != DBNull.Value)
                                {

                                    prop.SetValue(objHoliday, dt.Rows[row][dc.ColumnName], null);
                                }
                            }
                        }
                    }


                    ListHoliday.Add(objHoliday);
                }


            }
            catch (Exception ex)
            {
                throw ex;
            }

            return ListHoliday;
        }

i got an error at catch(Expression ex)

Posted 10-Jan-13 1:42am

renjimaramanan mr

Updated 10-Jan-13 2:11am

Manas Bhardwaj

v3

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Comments

OriginalGriff 10-Jan-13 6:45am

Where did you get the error? Which line?

[no name] 10-Jan-13 7:01am

it means there is some null value getting to your variable.

4 solutions

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This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Manas Bhardwaj · Answer 1 · 2013-01-10T02:16:00

1.) You didn't get error at catch. It happened much before that and was handled by catch block.
2.) It could be any where in the code. It's difficult for us to pin point where it could be. It could as early as in first statement:

ds.Tables[0];

where the ds could be null. To prevent that, you should also check if the object is not null like this:

DataTable dt;
if(ds != null)
{
    if(ds.Tables.count > 0)
    {
        dt = ds.Tables[0];
    }
}

3.) Use Visual Studio to debug the code, and you would know where the error occured. Look at the great article from Abhijit Jana here:
Mastering Debugging in Visual Studio 2010 - A Beginner's Guide[^]

Zafar Sultan · Answer 2 · 2013-01-10T01:48:00

Solution 1

Actually it is not possible to find out the error with this little code you have posted but my assumption is you should change this line

prop.SetValue(objHoliday, dt.Rows[row][dc.ColumnName], null);

to

prop.SetValue(objHoliday, dt.Rows[row][dc.ColumnName].ToString(), null);

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Posted 10-Jan-13 1:48am

Zafar Sultan

Comments

Manas Bhardwaj 10-Jan-13 7:18am

Your first statement is correct, but I don't think the assuption is correct. Your propsoed solution will still give an error if there is no row at specified index.

P.S. : I did not vote.

Zafar Sultan 10-Jan-13 7:31am

If there is no row at specified position is also an assumption and a wrong one because the OP is using for loop, for (int row = 0; row < dt.Rows.Count; row++). In case of 0 rows the control will never enter into the block. Anyways, I will vote for your solution

Maruthiram_99 · Answer 3 · 2013-01-10T02:07:00

Solution 2

Some null value is being passeed in your data table..check it ones by using quick watch

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Posted 10-Jan-13 2:07am

Maruthiram_99

syamrulezzz · Answer 4 · 2013-01-10T02:22:00

Solution 4

Hi,

HolidayReg objHoliday = null;

then it will work fine!!!!!!!!!

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Posted 10-Jan-13 2:22am

syamrulezzz

Comments

Manas Bhardwaj 10-Jan-13 7:43am

Please don't poullute the forum with irrelevent answers.

object reference not set to an instance of an object(i got an error through the below code)

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object reference not set to an instance of an object(i got an error through the below code)

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Solution 1

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