合并结构相同,不同,或多个DataTable

======下面是转贴的，结构相同的DataTable合并有个方法很简单的
======

DataTable.Merge (DataTable)将指定的DataTable与当前的 DataTable 合并//两个结构一样的DT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);
}
//两个结构不同的DT合并
/// <summary>
/// 将两个列不同的DataTable合并成一个新的DataTable
/// </summary>
/// <param name="dt1">表1</param>
/// <param name="dt2">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 ; //设置DT的名字
return dt3 ;
}

//多个 结构相同的DataTable合并

public DataTable GetAllEntrysDataTable()
{
DataTable newDataTable = GetEntrysDataTable(0).Clone();

object[] obj = new object[newDataTable.Columns.Count];

for (int i = 0; i < entryGroups.GetEntryGroupCount(); i++)
{
for (int j = 0; j < GetEntrysDataTable(i).Rows.Count; j++)
{
GetEntrysDataTable(i).Rows[j].ItemArray.CopyTo(obj, 0);
newDataTable.Rows.Add(obj);
}
}
return newDataTable;
}