How to prevent insertions of duplicate records into datatable

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C#

foreach (Selected s1 in objlistCropped)
                   {
                       string strImg2 = s1.Image;

                       if (strImg1 == strImg2)
                       {
                           dtPreInstallation.Rows.Add(strImg2, s.strText);
                       }
                    }

strImg1 = Img1.Jpeg,
I need to restrict adding img1.jpeg again if its already there in datatable.

Thanks in Advance

Posted 20-Jan-15 22:29pm

Renjith_R

Updated 20-Jan-15 23:12pm

v2

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2 solutions

Solution 1

You can use a Unique constraint[^] to do the job.

Posted 20-Jan-15 22:34pm

Wendelius

Comments

Renjith_R 21-Jan-15 5:29am

Its not working :(

George Jonsson 21-Jan-15 6:04am

It should work to make the column containing the file name unique, but you need to take care of the exception properly.
Can you you explain what is not working and how you expect it to work?

Wendelius 21-Jan-15 8:39am

Why do you say it's not working? Can you post the code you have tried.

In overall, I really don't suggest that you use the approach presented in solution 2. In my opinion you should rely on tested mechanisms that are built in in the framework instead of coding an alternative.

CHill60 21-Jan-15 7:08am

5'd - I've learned something today, thank you!

Wendelius 21-Jan-15 8:36am

Glad to be of service :)

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Vinay Raj K · Accepted Answer · 2015-01-20T23:25:00

C#

foreach (Selected s1 in objlistCropped)
            {
                //here you check the value is already added in the DataTable or not.
                bool duplicate = false;
                foreach (DataRow dr in dtPreInstallation.Rows)
                {
                    if (dr["columnName"].ToString() == "value") //compare the new value with the values in the datatable
                    {
                        duplicate = true;
                        return;
                    }
                }

                if (duplicate != true)
                {
                    dtPreInstallation.Rows.Add(strImg2, s.strText);
                }
                else
                {
                    //message : Value already exists
                }
            }

try this..