External list does not provide the export to excel – it displays the command but it is greyed out. So what can you do? Well just write your own custom action and put a application page behind it and now you can do anything.
At first you can provide an user interface which helps the user to select the external data he wants to export. The export itself can be done by using the response. Just look at the code below, i commented it:
//first, we tell what kind of file the response should write
string attach = “attachment;filename=myExcel.xls”;
Response.Buffer = true;
Response.ContentEncoding = System.Text.Encoding.UTF32;
Response.Charset = “”;
Response.ContentType = “application/vnd.ms-excel”;
Now we fill the first line with some data. To step to the next column use “\t”. The data comes from my business data catalog but it could also be a webservice.
Response.Write(mydata1.Replace(“\n”,string.Empty).Replace(“\r”, string.Empty)+ ” \t”);
Response.Write(mydata2.Replace(“\n”, string.Empty).Replace(“\r”, string.Empty) + ” \t”);
Response.Write(mydata3.Replace(“\n”, string.Empty).Replace(“\r”, string.Empty) + ” \t”);
Important notice: If your data is text and it contains line breaks, the line break will also take effect in your excel sheet. In mines it jumps to the next row instead stay in the column. Therefore i used the replace function, but i am sure there is a better option – Regex as example – and i would expect that it is possible to create a line break in the column itself.
But that’s just a post to give some basics with an really easy example.
..:: I LIKE SHAREPOINT ::..