Providing initial values for FieldValue tags is easily accomplished using pass-through attributes to set the property to be initialized (the "Text" property, for example) and specifying that the pass-through attribute to be "unencoded". However, for this to work, other pass-through attributes must also be specified to override the default behavior that FieldValue data is automatically loaded from and saved to the database.
LoadData="False". This suppresses the loading of the field’s data from the database. The LoadData pass-through attribute defaults to “True”, so setting it to “False” allows you to always initialize a field to a particular value.
SaveData="False". This suppresses saving the field’s data to the database. The SaveData pass-through attribute defaults to “True” for some FieldValue display styles and to “False” for others. Other FieldValue display styles, such as the Link Button, don’t allow SaveData=True. Setting it to “False” allows you to always save a particular value for the field, such as the logged in user ID or the current date and time.