DataTable比较当前行和下行是否一致 DataTable复制结构和复制数据

DataView dvNeed = dtView.DefaultView;
dvNeed.Sort = "EMPLOYEEID"; //排序用于下面当前行和下行比较 一般用来添加一行汇总行
DataTable dtNeed = dvNeed.ToTable(); //排序后的DataTable
DataTable dtFinally = dtNeed.Clone(); //复制dtNeed的结构 不复制数据 ，复制结构与数据用Copy()

for (int n = 0; n < dtNeed.Rows.Count; n++)
{
string EMPLOYEEID = dtNeed.Rows
["EMPLOYEEID"].ToString();
string COVERID = dtNeed.Rows
["COVERID"].ToString();
//判断是否最末一行
string CompareEMPLOYEEID = (n == dtNeed.Rows.Count - 1) ? "000000" : dtNeed.Rows[n + 1]["EMPLOYEEID"].ToString();
if (CompareEMPLOYEEID != EMPLOYEEID) //比较当前行与下行ID 不同ID 则添加汇总行
{
#region
DataRow drCount = dtFinally.NewRow();
//可以做相关统计信息
dtFinally.Rows.Add(drCount);
#endregion
}
}

//添加dtNeed中的数据到dtFinally
foreach (DataRow row in dtNeed.Rows)
{
dtFinally.Rows.Add(row.ItemArray);
}

//直接用微软提供的 DataTable.Merge实现
DataTable DataTable1 = new DataTable();
DataTable DataTable2 = new DataTable();
DataTable2.Merge(DataTable1);

//两个结构一样的DataTable合并
DataTable DataTable1 = new DataTable();
DataTable DataTable2 = new DataTable();
DataTable newDataTable = DataTable1.Clone();

object[] obj = new object[newDataTable.Columns.Count];
for (int i = 0; i < DataTable1.Rows.Count; i++)
{
DataTable1.Rows[i].ItemArray.CopyTo(obj,0);
newDataTable.Rows.Add(obj);
}
for (int i = 0; i < DataTable2.Rows.Count; i++)
{
DataTable2.Rows[i].ItemArray.CopyTo(obj,0);
newDataTable.Rows.Add(obj);
}
//或者
DataTable DataTable1 = new DataTable();
DataTable DataTable2 = new DataTable();

object[] obj = new object[DataTable1 .Columns.Count];
for (int i = 0; i < DataTable2.Rows.Count; i++)
{
DataTable2.Rows[i].ItemArray.CopyTo(obj,0);
DataTable1.Rows.Add(obj);
}

//两个结构不同的DataTable合并
/// <summary>
/// 将两个列不同的DataTable合并成一个新的DataTable
/// </summary>
/// <param name="dt1">Table表1</param>
/// <param name="dt2">Table表2</param>
/// <param name="DTName">合并后新的表名</param>
/// <returns></returns>

private DataTable UniteDataTable( DataTable dt1 ,DataTable dt2 ,string DTName)
{
DataTable dt3 = dt1.Clone();
for( int i = 0 ;i < dt2.Columns.Count ;i ++ )
{
dt3.Columns.Add( dt2.Columns[i].ColumnName ) ;
}
object[] obj = new object[dt3.Columns.Count];

for (int i = 0; i < dt1.Rows.Count; i++)
{
dt1.Rows[i].ItemArray.CopyTo(obj,0);
dt3.Rows.Add(obj);
}

if( dt1.Rows.Count >= dt2.Rows.Count )
{
for( int i = 0 ;i < dt2.Rows.Count ;i++ )
{
for( int j = 0 ;j < dt2.Columns.Count ;j ++ )
{
dt3.Rows[i][j+dt1.Columns.Count] = dt2.Rows[i][j].ToString() ;
}
}
}
else
{
DataRow dr3 ;
for( int i = 0 ;i < dt2.Rows.Count - dt1.Rows.Count ;i ++ )
{
dr3 = dt3.NewRow() ;
dt3.Rows.Add( dr3 ) ;
}
for( int i = 0 ;i < dt2.Rows.Count ;i++ )
{
for( int j = 0 ;j < dt2.Columns.Count ;j ++ )
{
dt3.Rows[i][j+dt1.Columns.Count] = dt2.Rows[i][j].ToString() ;
}
}
}
dt3.TableName = DTName ;
return dt3 ;
}