Default [PXDBInt] data field to Null value? - acumatica

Question

How can I have a numeric field allow and default to a Null / unspecified value?
When I add the control for this field to the screen it always defaults to "0" on new entities...
[PXDBInt]
[PXDefault(TypeCode.DBNull, "", PersistingCheck=PXPersistingCheck.Nothing)]
[PXUIField(DisplayName="Nullable Int")]

Answer 1

The issue here appears to be whether the field is in a Form area or Grid table. In a Grid a null-value is rendered as an empty cell and persists as null if left empty. However, when in a Form area a null value is rendered with "0". If the value is changed attempting to then change it back to empty/null results in a zero value persisting to the database.
The solution I found was when creating the control instead of using a PXNumberEdit type field, changing it to a PXTextEdit field and setting the TextMode property to "Number" gave the desired effect. Null values would render as empty and are distinguished from actual zero values.

Answer 2

There is AllowNull attribute in px:PXNumberEdit control.
In this implementation you do not even need to add the PXDefault attribute to your field.
I added MinValue = 1, MaxValue = 999999 in c# code and DisplayFormat="n0" MaxLength="6" in .aspx because of my task, it should work without this.
<px:PXNumberEdit runat="server" ID="edUsrCapacity" DataField="UsrCapacity"
DisplayFormat="n0" MaxLength="6" AllowNull="True" />
[PXDBInt(MinValue = 1, MaxValue = 999999)]
[PXUIField(DisplayName = Messages.FsEquipment.Capacity)]
public virtual int? UsrCapacity
{
get;
set;
}
public abstract class usrCapacity : BqlInt.Field<usrCapacity>
{
}

Answer 3

The default value for all fields is null unless you force a value with PXDefault.
If you remove the [PXDefault] attribute it will automatically default to null.
Make sure your value is defined as a int? and not int as well. the "?" denotes it as "nullable"
For example:
#region CurrentConfigRevision
public abstract class currentConfigRevision : PX.Data.IBqlField
{
}
protected int? _CurrentConfigRevision;
[PXDBInt]
[PXUIField(DisplayName="Current Revision")]
public virtual int? CurrentConfigRevision
{
get
{
return this._CurrentConfigRevision;
}
set
{
this._CurrentConfigRevision = value;
}
}
#endregion
This will always have a null value unless the user specifies in the interface (or it's set via code)