連線兩個DataTable表

在c#中把兩個datatable連線起來，相當於sql的inner join方法

public static datatable join (datatable first, datatable second, datacolumn fjc, datacolumn sjc)

);datacolumn parentcolumns = new datacolumn[fjc.length];

for(int i = 0; i < parentcolumns.length; i++)

parentcolumns[i] = ds.tables[0].columns[fjc[i].columnname];

datacolumn childcolumns = new datacolumn[sjc.length];

for(int i = 0; i < childcolumns.length; i++)

childcolumns[i] = ds.tables[1].columns[sjc[i].columnname];

//建立關聯

datarelation r = new datarelation(string.empty,parentcolumns,childcolumns,false);

ds.relations.add(r);

//為關聯表建立列

for(int i = 0; i < first.columns.count; i++)

table.columns.add(first.columns[i].columnname, first.columns[i].datatype);

for(int i = 0; i < second.columns.count; i++)

//看看有沒有重複的列，如果有在第二個datatable的column的列明後加_second

if(!table.columns.contains(second.columns[i].columnname))

table.columns.add(second.columns[i].columnname, second.columns[i].datatype);

else

table.columns.add(second.columns[i].columnname + "_second", second.columns[i].datatype);

}table.beginloaddata();

foreach(datarow firstrow in ds.tables[0].rows)

//得到行的資料

datarow childrows = firstrow.getchildrows(r);

if(childrows != null && childrows.length > 0)

object parentarray = firstrow.itemarray;

foreach(datarow secondrow in childrows)

object secondarray = secondrow.itemarray;

object joinarray = new object[parentarray.length+secondarray.length];

array.copy(parentarray,0,joinarray,0,parentarray.length);

array.copy(secondarray,0,joinarray,parentarray.length,secondarray.length);

table.loaddatarow(joinarray,true);

table.endloaddata();

return table;

public static datatable join (datatable first, datatable second, datacolumn fjc, datacolumn sjc)

return join(first, second, new datacolumn, new datacolumn);

public static datatable join (datatable first, datatable second, string fjc, string sjc)

return join(first, second, new datacolumn, new datacolumn);}}

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