Question

I want to search rows in my DataTable.

I’ve tried this:

 protected void imggastsuche_Click(object sender, EventArgs e) 
        {
            string searchstring = txtgastsuche.Text;

            DataTable tb = DataBaseManager.GetDataTable(mysqlconnectionstring);

            DataRow[] foundRows = tb.Select("FIRSTNAME,LASTNAME,NAME,COMPANY,TIMEFROM,TIMETO,CREATOR Like '%" + searchstring + "%'");

            tb = foundRows.CopyToDataTable();

            this.ListView.DataSource = tb;
            this.ListView.DataBind();

        }

But I have an error in my string.

What can I do if I want to search these columns?

Answer 1

You get the error because the parameter to Select is the filterExpression and you have passed all columns. Understand the filterExpression as a WHERE clause in sql. You want all columns but you want to filter by just one. You get all columns anyway since they are all part of the DataTable/DataView so you don’t need to list them explicitely.

You could either use the DataTable.Select, DatView.RowFilter methods or LINQ-to-DataSet:

LINQ-To-DataSet (which i prefer):

var filtered = tb.AsEnumerable()
    .Where(r => r.Field<String>("CREATOR").Contains(searchstring));

ADO.NET(DataTable.Select):

DataRow[] filteredRows = tb.Select("CREATOR LIKE '%" + searchstring + "%'");

ADO.NET(DataView.RowFilter):

 tb.DefaultView.RowFilter = "CREATOR LIKE '%" + searchstring + "%'";

---

If you want to search for this string in any column instead:

DataRow[] filteredRows = tb.Select("FIRSTNAME LIKE '%" + searchstring + "%' OR LASTNAME LIKE '%" + searchstring + "%' OR NAME LIKE '%" + searchstring + "%' OR COMPANY LIKE '%" + searchstring + "%' OR CREATOR LIKE '%" + searchstring + "%'");

The same with Linq:

var filtered = tb.AsEnumerable()
    .Where(r => r.Field<String>("FIRSTNAME").Contains(searchstring)
           ||   r.Field<String>("LASTNAME").Contains(searchstring))
           ||   r.Field<String>("NAME").Contains(searchstring)
           ||   r.Field<String>("COMPANY").Contains(searchstring)
           ||   r.Field<String>("CREATOR").Contains(searchstring));