如何防止将重复记录插入到数据表中 [英] How to prevent insertions of duplicate records into datatable

问题描述

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

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

strImg1 = Img1.Jpeg，
我需要限制再添加img1.jpeg，如果它已经存在于数据表中。



先谢谢

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

Thanks in Advance

推荐答案

您可以使用唯一约束 [ ^ ]来完成这项工作。

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

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
                }
            }

试试这个..

try this..

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