Using C# to write to a longtext column (no replies)

Hi,

I'm using C# to write to a table with 4 columns. Writing to 3 of the columns work perfectly, but I can't make things work for the 4th column.

The 4th column is datatype longtext.

There are already rows in the table with data. For a row with existing data, the 4th column look like this:
a:5:{s:12:"post_name";s:3:"301";s:7:"address";s:35:"Lergravsparken 57, 2300 København S";s:11:"gpsLatitude";s:9:"55.664321";s:12:"gpsLongitude";s:9:"12.625780";s:3:"web";s:24:"http://www.ashiraoure.dk";}

I have tried to write the same data to the 4th column, but it didn't work (a string with the same text).

Any ideas how I can save data properly to the 4th column?

Thanks,
Mads