Test for a null value

Applies to Dynamics 365 (online), version 9.x

The following code example shows how to test for a null value by using the FilterExpression and QueryByAttribute classes.

Example

Use this code to test for equality by using the FilterExpression class.

FilterExpression null_filter = new FilterExpression(LogicalOperator.And);   
null_filter.FilterOperator = LogicalOperator.And;   
null_filter.AddCondition("leadid", ConditionOperator.Null);  
  

Example

Use this code to test for inequality by using the FilterExpression class.

  
FilterExpression filter = new FilterExpression(LogicalOperator.And);   
filter.FilterOperator = LogicalOperator.And;   
filter.AddCondition("leadid", ConditionOperator.NotNull);  

Example

Use this code to test for equality by using the QueryByAttribute class.

  
QueryByAttribute qba = new QueryByAttribute("account");   
qba.ColumnSet = new ColumnSet("name","address1_stateorprovince");   
qba.AddAttributeValue("donotfax", null);  

See also

Building Queries with QueryExpression
Page large result sets with QueryExpression