Cannot perform '=' operation on System.TimeSpan and System.String.

Question

User1487175000 posted

Hi,

I have following datatable table structure. Its have two timespan columns. Later i try to filter datatbale based on these timespan column. Then i get the following error.

dt_checkout = new DataTable();
dt_checkout.Columns.Add(new DataColumn("buildingID", typeof(Int32)));
dt_checkout.Columns.Add(new DataColumn("bookingDate", typeof(DateTime)));
dt_checkout.Columns.Add(new DataColumn("bookingStartTime", typeof(TimeSpan)));
dt_checkout.Columns.Add(new DataColumn("bookingEndTime", typeof(TimeSpan)));

// filter
dt_checkout.Select("buildingID=" + bID + " AND bookingDate='" + bDate.ToString("yyyy-MM-dd") + "' AND bookingStartTime='" + sTime.ToString() + "' AND bookingEndTime='" + eTime.ToString() + "'");

Cannot perform '=' operation on System.TimeSpan and System.String.

Answer 1

User-1716253493 posted

Are sTime and eTime time span?

Check what the sTime.ToString() result

TimeSpan is duration

Answer 2

User1487175000 posted

Yes they are timespain duration.

Answer 3

User-1174608757 posted

Hi,Shahid Majeed

As far as I known ,timespan has methods for comparisons but it  does not  have the use of the operators which means you could n't compare the type of timespan.

So, in this case , you could just use long type to represent the duration. You could write as below:

 protected void Page_Load(object sender, EventArgs e)
        {
           DataTable dt_checkout = new DataTable();        
           dt_checkout.Columns.Add(new DataColumn("bookingStartTime", typeof(long)));
            DataRow row = dt_checkout.NewRow();
            
            row["bookingStartTime"] = "3600";
            dt_checkout.Rows.Add(row);
    
           DataRow[] rows= dt_checkout.Select("bookingStartTime= '"+ long.Parse(a1.Text)+"'");

        }

Best Regards

Wei Zhang

Answer 4

User-158764254 posted

maybe give Linq a try:

https://stackoverflow.com/questions/40756170/datatable-select-filter-where-column-timespan