如何比较2个dataTables

Question

我有2个数据表,我只想知道它们是否相同."相同",我的意思是它们具有完全相同的行数,每列中的数据完全相同或不相同.我想写(找到)一个接受两个表并返回一个布尔值的方法.

如何以这种方式比较2个数据表？两者都有相同的模式.

Answer 1

 public static bool AreTablesTheSame( DataTable tbl1, DataTable tbl2)
 {
    if (tbl1.Rows.Count != tbl2.Rows.Count || tbl1.Columns.Count != tbl2.Columns.Count)
                return false;


    for ( int i = 0; i < tbl1.Rows.Count; i++)
    {
        for ( int c = 0; c < tbl1.Columns.Count; c++)
        {
            if (!Equals(tbl1.Rows[i][c] ,tbl2.Rows[i][c]))
                        return false;
        }
     }
     return true;
  }

Answer 2

如果您将DataTable作为函数返回,您可以:

DataTable dataTable1; // Load with data
DataTable dataTable2; // Load with data (same schema)

// Fast check for row count equality.
if ( dataTable1.Rows.Count != dataTable2.Rows.Count) {
    return true;
}

var differences =
    dataTable1.AsEnumerable().Except(dataTable2.AsEnumerable(),
                                            DataRowComparer.Default);

return differences.Any() ? differences.CopyToDataTable() : new DataTable();

Answer 3

您需要循环遍历每个表的行,然后遍历该循环中的每个列以比较各个值.

这里有一个代码示例:http://canlu.blogspot.com/2009/05/how-to-compare-two-datatables-in-adonet.html

Answer 4

尝试使用 linq to Dataset

(from b in table1.AsEnumerable()  
    select new { id = b.Field<int>("id")}).Except(
         from a in table2.AsEnumerable() 
             select new {id = a.Field<int>("id")})

查看这篇文章：使用 LINQ 比较数据集

Answer 5

OP,MAW74656最初在问题机构中回答了这个答案,以回应已接受的答案,如本评论所述:

我使用它并编写了一个公共方法来调用代码并返回布尔值.

OP的答案是:

使用代码:

public bool tablesAreTheSame(DataTable table1, DataTable table2)
{
    DataTable dt;
    dt = getDifferentRecords(table1, table2);

    if (dt.Rows.Count == 0)
        return true;
    else
        return false;
}

//Found at http://canlu.blogspot.com/2009/05/how-to-compare-two-datatables-in-adonet.html
private DataTable getDifferentRecords(DataTable FirstDataTable, DataTable SecondDataTable)
{
    //Create Empty Table     
    DataTable ResultDataTable = new DataTable("ResultDataTable");

    //use a Dataset to make use of a DataRelation object     
    using (DataSet ds = new DataSet())
    {
        //Add tables     
        ds.Tables.AddRange(new DataTable[] { FirstDataTable.Copy(), SecondDataTable.Copy() });

        //Get Columns for DataRelation     
        DataColumn[] firstColumns = new DataColumn[ds.Tables[0].Columns.Count];
        for (int i = 0; i < firstColumns.Length; i++)
        {
            firstColumns[i] = ds.Tables[0].Columns[i];
        }

        DataColumn[] secondColumns = new DataColumn[ds.Tables[1].Columns.Count];
        for (int i = 0; i < secondColumns.Length; i++)
        {
            secondColumns[i] = ds.Tables[1].Columns[i];
        }

        //Create DataRelation     
        DataRelation r1 = new DataRelation(string.Empty, firstColumns, secondColumns, false);
        ds.Relations.Add(r1);

        DataRelation r2 = new DataRelation(string.Empty, secondColumns, firstColumns, false);
        ds.Relations.Add(r2);

        //Create columns for return table     
        for (int i = 0; i < FirstDataTable.Columns.Count; i++)
        {
            ResultDataTable.Columns.Add(FirstDataTable.Columns[i].ColumnName, FirstDataTable.Columns[i].DataType);
        }

        //If FirstDataTable Row not in SecondDataTable, Add to ResultDataTable.     
        ResultDataTable.BeginLoadData();
        foreach (DataRow parentrow in ds.Tables[0].Rows)
        {
            DataRow[] childrows = parentrow.GetChildRows(r1);
            if (childrows == null || childrows.Length == 0)
                ResultDataTable.LoadDataRow(parentrow.ItemArray, true);
        }

        //If SecondDataTable Row not in FirstDataTable, Add to ResultDataTable.     
        foreach (DataRow parentrow in ds.Tables[1].Rows)
        {
            DataRow[] childrows = parentrow.GetChildRows(r2);
            if (childrows == null || childrows.Length == 0)
                ResultDataTable.LoadDataRow(parentrow.ItemArray, true);
        }
        ResultDataTable.EndLoadData();
    }

    return ResultDataTable;
}