Datatable is converted into CSV and binary streams, and Excel and transfer are exported.

/// <Summary>
/// 1 Changes to CSV file stream
/// 2 zip Compression
/// </Summary>
/// <Param name = "ds"> </param>
/// <Returns> </returns>
Private byte [] tocsvfilestream (datatable ds, Dictionary <string, Object> DIC)
{
// Replace the Chinese column header name
DS = datatablecolumename_en2ch (DS, DIC );

// Datatable-> CSV data
Byte [] DATA = exportdatatocsvstream (DS );

// After processing, delete and clear the cache
DS = NULL;
GC. Collect ();

// Zip
Byte [] zipdata = csharpziper. zipdata (data, 6 );
Return zipdata;
}

# Region datatalbe-> CSV

///

// export the CSV format [file stream]
///
//
//
private byte [] exportdatatocsvstream (datatable)
{< br> If (datatable = NULL | datatable. columns. count = 0 | datatable. rows. count = 0)
{< br> return NULL;
}

Streamex writer = new streamex (true );
String column = string. empty;
Column = createcolumn (datatable );
Writer. Write. Write (1); // 1 Head
Writer. writestring (column );

String line = string. empty;
Writer. Write. Write (datatable. Rows. Count); // row count
Foreach (datarow row in datatable. Rows)
{
Line = createline (ROW );
Writer. writestring (line );
}

return writer. memorystreambuffer;
}

private string createline (datarow row)
{< br> int COUNT = m_list.count;
stringbuilder sb = new stringbuilder ();
for (INT I = 0; I {< br> metaitem item = m_list [I];
If (item = NULL |! Item. showflag | item. name. tolower (). trim () = "customcolumn_number")
{< br> continue;
}< br> int Index = mapping [item. name];

Object text = Index =-1? Dbnull. Value: Row [item. Name];
If (item! = NULL)
{
If (! Item. showflag)
Continue;
Else if (! (Text is dbnull )&&! String. isnullorempty (item. showformat ))
{
Switch (item. datatype)
{
Case datatype. einteger:
TEXT = (INT) text). tostring (item. showformat );
Break;
Case datatype. elong:
TEXT = (long) text). tostring (item. showformat );
Break;
Case datatype. edouble:
TEXT = (double) text). tostring (item. showformat );
Break;
Case datatype. edatetime:
TEXT = (datetime) text). tostring (item. showformat );
Break;
}
}
}

If (I = count-1)
{
SB. appendformat ("{0}", text );
}
Else
{
SB. appendformat ("{0} {1}", text, splitchar [0]);
}
}

Return sb. tostring ();
}

Dictionary <string, int> mapping = new dictionary <string, int> ();
Private string createcolumn (datatable)
{
Mapping = new dictionary <string, int> ();
Int COUNT = m_list.count;
Stringbuilder sb = new stringbuilder ();
For (INT I = 0; I <count; I ++)
{
Metaitem item = m_list [I];
If (item = NULL |! Item. showflag | item. Name. tolower (). Trim () = "customcolumn_number ")
{
Continue;
}
Mapping [item. Name] = getcolumenameindex (datatable, item. Name );
String text = item. text;
If (I = count-1)
{
SB. appendformat ("{0}", text );
}
Else
{
SB. appendformat ("{0} {1}", text, splitchar [0]);
}
}

Return sb. tostring ();
}

private int getcolumenameindex (datatable, string columanname)
{< br> columanname = columanname. tolower (). trim ();
for (INT I = 0; I {< br> datacolumn Col = datatable. columns [I];
If (Col. columnname. tolower (). trim () = columanname)
{< br> return I;
}< br> return-1;
}

private char [] splitchar
{< br> Get
{< br> return New char [] {'\ t '};
}< BR ># endregion