Finding a field in a dataset c #
I am querying a mySQL database and storing the response in a datatable. I need to check a specific column to check if it is empty or null.Below is what I am doing
DataTable dataTab = new DataTable("ServiceOrderProtocol");
string strQuery = "select OrderID, ServiceOrder, ExternalID, Project_key, ProjectType from ServiceOrder;";
using (MySqlCommand cmd = new MySqlCommand(strQuery, conn))
{
using (MySqlDataAdapter sqlDa = new MySqlDataAdapter(cmd))
{
sqlDa.Fill(dataTab);
return dataTab;
}}
Now I'm not sure how to check if the ExternalID field returned from the request stored in the dataTab is null or empty.
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If you want to know if any of the rows in the table contain a null value in the field ExternalID
:
bool anyNullExternalID = dataTab.AsEnumerable().Any(r => r.IsNull("ExternalID"));
If you want to know if all values are null:
bool allNullExternalID = dataTab.AsEnumerable().All(r => r.IsNull("ExternalID"));
If you want all strings to be null:
IEnumerable<DataRow> allNullExternalIDRows = dataTab.AsEnumerable()
.Where(r => r.IsNull("ExternalID"));
If it is not int
(e.g. title) but string
you want to include the null
empty line as well, add|| string.IsNullOrEmpty(r.Field<string>("ExternalID"))
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