如何在c#中加入两个DataTable？

概述如何保留外部连接(我认为是外部加入,但我不是100％确定)两个数据表与以下表格和条件,同时保留两个表中的所有列？ dtblLeft： id col1 anotherColumn2 1 1 any2 2 1 any2 3 2 any2 4 3 any2 5 3 any2 6 3 any 如何保留外部连接(我认为是外部加入,但我不是100％确定)两个数据表与以下表格和条件,同时保留两个表中的所有列？

dtblleft：

ID   col1   anotherColumn2 1    1      any2 2    1      any2 3    2      any2 4    3      any2 5    3      any2 6    3      any2 7           any2

dtblRight：

col1   col2      anotherColumn1 1      Hi        any1 2      Bye       any1 3      Later     any1 4      Never     any1

dtblJoined：

ID   col1  col2     anotherColumn1     anotherColumn2 1    1     Hi       any1               any2 2    1     Hi       any1               any2 3    2     Bye      any1               any2 4    3     Later    any1               any2 5    3     Later    any1               any2 6    3     Later    any1               any2 7                                      any2

条件：

>在dtblleft中,col1不需要具有唯一的值.
>在dtblRight中,col1具有唯一的值.
>如果dtblleft在col1中缺少一个外键,或者它在dtblRight中不存在一个外键,那么将插入空或空字段.
>加入col1.

我可以使用常规的Datatable *** 作,liNQ或其他.

我尝试了这个,但它删除重复：

dtblA.PrimaryKey = new DataColumn[] {dtblA.Columns["col1"]}Datatable dtblJoined = new Datatable();dtblJoined.Merge(dtblA,false,MissingSchemaAction.AdDWithKey);dtblJoined.Merge(dtblB,MissingSchemaAction.AdDWithKey);

编辑1：

这是接近我所想要的,但它只有一个表的列(发现在这link)：

dtblJoined = (from t1 in dtblA.Rows.Cast<DaTarow>()                  join t2 in dtblB.Rows.Cast<DaTarow>() on t1["col1"] equals t2["col1"]                  select t1).copyToDatatable();

编辑2：

这个link的答案似乎适用于我,但我不得不改变一下如下：

Datatable targettable = dtblA.Clone();var dt2Columns = dtblB.Columns.OfType<DataColumn>().Select(dc =>new DataColumn(dc.Columnname,dc.DataType,dc.Expression,dc.ColumnMapPing));var dt2FinalColumns = from dc in dt2Columns.AsEnumerable()                   where targettable.Columns.Contains(dc.Columnname) == false                   select dc;targettable.Columns.AddRange(dt2FinalColumns.ToArray());var rowData = from row1 in dtblA.AsEnumerable()                          join row2 in dtblB.AsEnumerable()                          on row1["col1"] equals row2["col1"]                          select row1.ItemArray.Concat(row2.ItemArray.Where(r2 => row1.ItemArray.Contains(r2) == false)).ToArray(); foreach (object[] values in rowData)      targettable.Rows.Add(values);

我也发现这个link,我可能会尝试,因为它似乎更简洁.

编辑3(11/18/2013)：

更新表以反映更多的情况.

解决方法 感谢所有的帮助.这是我根据多种资源提出的：

public static class DatatableHelper{    public enum JoinType    {        /// <summary>        /// Same as regular join. Inner join produces only the set of records that match in both table A and table B.        /// </summary>        Inner = 0,/// <summary>        /// Same as left Outer join. left outer join produces a complete set of records from table A,with the matching records (where available) in table B. If there is no match,the right sIDe will contain null.        /// </summary>        left = 1    }    /// <summary>    /// Joins the passed in Datatables on the colToJoinOn.    /// <para>Returns an appropriate Datatable with zero rows if the colToJoinOn does not exist in both tables.</para>    /// </summary>    /// <param name="dtblleft"></param>    /// <param name="dtblRight"></param>    /// <param name="colToJoinOn"></param>    /// <param name="joinType"></param>    /// <returns></returns>    /// <remarks>    /// <para>https://stackoverflow.com/questions/2379747/create-combined-datatable-from-two-datatables-joined-with-linq-c-sharp?rq=1</para>    /// <para>http://msdn.microsoft.com/en-us/library/vstudio/bb397895.aspx</para>    /// <para>http://www.Codinghorror.com/blog/2007/10/a-visual-explanation-of-sql-joins.HTML</para>    /// <para>https://stackoverflow.com/questions/406294/left-join-and-left-outer-join-in-sql-server</para>    /// </remarks>    public static Datatable JoinTwoDatatablesOnOneColumn(Datatable dtblleft,Datatable dtblRight,string colToJoinOn,JoinType joinType)    {        //Change column name to a temp name so the liNQ for getting row data will work properly.        string strTempColname = colToJoinOn + "_2";        if (dtblRight.Columns.Contains(colToJoinOn))            dtblRight.Columns[colToJoinOn].Columnname = strTempColname;        //Get columns from dtblleft        Datatable dtblResult = dtblleft.Clone();        //Get columns from dtblRight        var dt2Columns = dtblRight.Columns.OfType<DataColumn>().Select(dc => new DataColumn(dc.Columnname,dc.ColumnMapPing));        //Get columns from dtblRight that are not in dtblleft        var dt2FinalColumns = from dc in dt2Columns.AsEnumerable()                              where !dtblResult.Columns.Contains(dc.Columnname)                              select dc;        //Add the rest of the columns to dtblResult        dtblResult.Columns.AddRange(dt2FinalColumns.ToArray());        //No reason to continue if the colToJoinOn does not exist in both Datatables.        if (!dtblleft.Columns.Contains(colToJoinOn) || (!dtblRight.Columns.Contains(colToJoinOn) && !dtblRight.Columns.Contains(strTempColname)))        {            if (!dtblResult.Columns.Contains(colToJoinOn))                dtblResult.Columns.Add(colToJoinOn);            return dtblResult;        }        switch (joinType)        {            default:            case JoinType.Inner:                #region Inner                //get row data                //To use the Datatable.AsEnumerable() extension method you need to add a reference to the System.Data.DataSetExtension assembly in your project.                 var rowDataleftInner = from rowleft in dtblleft.AsEnumerable()                                       join rowRight in dtblRight.AsEnumerable() on rowleft[colToJoinOn] equals rowRight[strTempColname]                                       select rowleft.ItemArray.Concat(rowRight.ItemArray).ToArray();                //Add row data to dtblResult                foreach (object[] values in rowDataleftInner)                    dtblResult.Rows.Add(values);                #endregion                break;            case JoinType.left:                #region left                var rowDataleftOuter = from rowleft in dtblleft.AsEnumerable()                                       join rowRight in dtblRight.AsEnumerable() on rowleft[colToJoinOn] equals rowRight[strTempColname] into gj                                       from subRight in gj.DefaultIfEmpty()                                       select rowleft.ItemArray.Concat((subRight== null) ? (dtblRight.NewRow().ItemArray) :subRight.ItemArray).ToArray();                //Add row data to dtblResult                foreach (object[] values in rowDataleftOuter)                    dtblResult.Rows.Add(values);                #endregion                break;        }        //Change column name back to original        dtblRight.Columns[strTempColname].Columnname = colToJoinOn;        //Remove extra column from result        dtblResult.Columns.Remove(strTempColname);        return dtblResult;    }}

编辑3：

该方法现在可以正常工作,并且当表具有2000行时,该方法仍然很快.任何建议/建议/改进将不胜感激.

编辑4：

我有一些情况导致我意识到,以前的版本是真正做一个内在的联合.该功能已被修改以解决该问题.我使用这个link的信息来弄清楚.

总结

以上是内存溢出为你收集整理的如何在c#中加入两个DataTable？全部内容，希望文章能够帮你解决如何在c#中加入两个DataTable？所遇到的程序开发问题。

如果觉得内存溢出网站内容还不错，欢迎将内存溢出网站推荐给程序员好友。