Actually this is not a question. I just want to help other asp.net users.
This solution tested with dhtmlxgrid ver 1.6 professional. (IE and FF)
Make sure you’ve backup your orginal files before modification.
Step 1
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Firstly, You have to edit dhtmlxgrid_nxml.js file for remove extra \n lines from data.
Replace----------------------------------------------##########################
dhtmlXGridObject.prototype.serializeToCSV = function(labels){
this.editStop()
if (labels)
this._agetm=“getTitle”;
else if (this._mathSerialization)
this._agetm=“getMathValue”;
else this._agetm=“getValue”;
var out=[];
if (this._csvHdr){
var a=[]; var b=this.hdr.rows[1].cells;
for (var i=0; i<b.length; i++)
if ((!this._srClmn)||(this._srClmn[i]))
{
var cellContent = _isIE?b[i].innerText:b[i].textContent;
cellContent = replace(cellContent,"\n"," “);
a.push(cellContent);
}
out.push(a.join(this.csv.cell));
}
//rows collection
var i=0;
var leni=this.rowsBuffer.length;
for(i; i<leni; i++){
var temp=this._serializeRowToCVS(null,i);
temp = replace(temp,”\n"," “);
if (temp!=”") out.push(temp);
}
return out.join(this.csv.row);
}
with----------------------------------------------##########################
function replace(string,text,by) {
var strLength = string.length, txtLength = text.length;
if ((strLength == 0) || (txtLength == 0)) return string;
var i = string.indexOf(text);
if ((!i) && (text != string.substring(0,txtLength))) return string;
if (i == -1) return string;
var newstr = string.substring(0,i) + by;
if (i+txtLength < strLength)
newstr += replace(string.substring(i+txtLength,strLength),text,by);
return newstr;
}
dhtmlXGridObject.prototype.serializeToCSV = function(labels){
this.editStop()
if (labels)
this._agetm=“getTitle”;
else if (this._mathSerialization)
this._agetm=“getMathValue”;
else this._agetm=“getValue”;
var out=[];
if (this._csvHdr){
var a=[]; var b=this.hdr.rows[1].cells;
for (var i=0; i<b.length; i++)
if ((!this._srClmn)||(this._srClmn[i]))
{
var cellContent = _isIE?b[i].innerText:b[i].textContent;
cellContent = replace(cellContent,"\n"," “);
a.push(cellContent);
}
out.push(a.join(this.csv.cell));
}
//rows collection
var i=0;
var leni=this.rowsBuffer.length;
for(i; i<leni; i++){
var temp=this._serializeRowToCVS(null,i);
temp = replace(temp,”\n"," “);
if (temp!=”") out.push(temp);
}
return out.join(this.csv.row);
}
Step 2
##############################################################################
Add this function to your master js file or add it to your page.
function ExportToExcel(grid){
grid.setCSVDelimiter("|");
grid.enableCSVHeader(true);
return grid.serializeToCSV(true);
}
Step 3
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Add this c# code to your appcode.
It’s silly but works 
public static void ExportToExcel(string excelData, string fileName)
{
DataTable dt = new DataTable();
StringReader tr = new StringReader(excelData);
string line;
while ((line = tr.ReadLine()) != null)
{
string[] items = line.Split(’|’);
if (dt.Columns.Count == 0)
{
// Create the data columns for the data table based on the number of items
// on the first line of the file
for (int i = 0; i < items.Length; i++)
dt.Columns.Add(new DataColumn(“Column” + i, typeof(string)));
}
dt.Rows.Add(items);
}
System.Web.UI.WebControls.DataGrid grid = new System.Web.UI.WebControls.DataGrid();
grid.HeaderStyle.Font.Bold = true;
grid.ShowHeader = false;
grid.DataSource = dt;
grid.DataMember = dt.TableName;
grid.DataBind();
HttpContext.Current.Response.Clear();
HttpContext.Current.Response.AddHeader(“content-disposition”, “attachment;filename=” + fileName + “.xls”);
HttpContext.Current.Response.Charset = “”;
HttpContext.Current.Response.Cache.SetCacheability(HttpCacheability.NoCache);
HttpContext.Current.Response.ContentType = “application/vnd.ms-excel”;
HttpContext.Current.Response.ContentEncoding = Encoding.UTF8;
System.IO.StringWriter stringWrite = new System.IO.StringWriter();
System.Web.UI.HtmlTextWriter htmlWrite = new HtmlTextWriter(stringWrite);
stringWrite.Write("<meta http-equiv=“content-type” content=“text/html; charset=utf-8”>");
grid.RenderControl(htmlWrite);
stringWrite.Write("");
HttpContext.Current.Response.Write(stringWrite.ToString());
HttpContext.Current.Response.Flush();
HttpContext.Current.Response.End();
}
Step 4
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Add hidden to your page
Step 5
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this is your server side button html
<asp:Button CssClass=“btnExcel” ID=“btnExcel” runat=“server” Text=“Export to Excel” OnClientClick=“ToExcel();return true;” UseSubmitBehavior=“true” OnClick=“btnExcel_Click”></asp:Button>
code:
protected void btnExcel_Click(object sender, EventArgs e)
{
string excelData = hdnExcel.Value;
MyHelperFile.ExportToExcel(excelData, Page.Title.Trim(’ '));
}
Finished
##############################################################################
That’s it. It’s look like complicated but it’s very easy.
Mehmet Kut - mehmetkut@gmail.com
The same effect can be achieved without code modification.
You can skip step 1, and modify step 2 as
function ExportToExcel(grid){
grid.csv.cell="|";
grid.csv.row="\f";
grid.enableCSVHeader(true);
var csv=grid.serializeToCSV(true);
return csv.replace(/\n/g,"").replace(/\f/g,"\n"); //replace new lines in data, and set new lines as row separators
}