DataTable 合并、分页

///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 ;
}

/// <summary>
/// 将两个列不同的DataTable通过两个表中对应的关键字值进行拼接
/// </summary>
/// <param name="dt1">表1</param>
/// <param name="dt2">表2</param>
/// <param name="dt1Name">表1中的关键字</param>
/// <param name="dt2Name">表2中的关键字</param>
/// <returns></returns>
private DataTable UniteDataTable(DataTable dt1, DataTable dt2, string dt1Name, string dt2Name)
{
DataTable dt3 = dt1.Copy();
int index = 0;
for (int i = 0; i < dt2.Columns.Count; i++)
{
index = 0;
while (dt1.Columns.Contains(dt2.Columns[i].ColumnName+(index==0?"":index.ToString())))
{
index++;
}
dt3.Columns.Add(dt2.Columns[i].ColumnName+(index==0?"":index.ToString()));
}
object[] obj = new object[dt3.Columns.Count];

for (int i = 0; i < dt2.Rows.Count; i++)
{
DataRow[] dr1 = dt2.Select(dt2Name + "='" + dt3.Rows[i][dt1Name]+"'");
if (dr1 != null && dr1.Count() > 0)
{
for (int j = 0; j < dr1[0].Table.Columns.Count; j++)
{
dt3.Rows[i][j + dt1.Columns.Count] = dr1[0][j].ToString();
}
}
}
return dt3;
}

///PageIndex表示第几页，PageSize表示每页的记录数
public DataTable GetPagedTable(DataTable dt, int PageIndex, int PageSize)

{
if (PageIndex == 0)
return dt;//0页代表每页数据，直接返回

DataTable newdt = dt.Copy();
newdt.Clear();//copy dt的框架

int rowbegin = (PageIndex - 1) * PageSize;
int rowend = PageIndex * PageSize;

if (rowbegin >= dt.Rows.Count)
return newdt;//源数据记录数小于等于要显示的记录，直接返回dt

if (rowend > dt.Rows.Count)
rowend = dt.Rows.Count;
for (int i = rowbegin; i <= rowend - 1; i++)
{
DataRow newdr = newdt.NewRow();
DataRow dr = dt.Rows[i];
foreach (DataColumn column in dt.Columns)
{
newdr[column.ColumnName] = dr[column.ColumnName];
}
newdt.Rows.Add(newdr);
}
return newdt;
}