Expression is a value and therefore cannot be the target of an assignment
A statement attempts to assign a value to an expression. You can assign a value only to a writable variable, property, or array element at run time. The following example illustrates how this error can occur.
Dim yesterday As Integer ReadOnly maximum As Integer = 45 yesterday + 1 = DatePart(DateInterval.Day, Now) ' The preceding line is an ERROR because of an expression on the left. maximum = 50 ' The preceding line is an ERROR because maximum is declared ReadOnly.
Similar examples could apply to properties and array elements.
Indirect Access. Indirect access through a value type can also generate this error. Consider the following code example, which attempts to set the value of Point by accessing it indirectly through Location.
' Assume this code runs inside Form1. Dim exitButton As New System.Windows.Forms.Button() exitButton.Text = "Exit this form" exitButton.Location.X = 140 ' The preceding line is an ERROR because of no storage for Location.
The last statement of the preceding example fails because it creates only a temporary allocation for the Point structure returned by the Location property. A structure is a value type, and the temporary structure is not retained after the statement runs. The problem is resolved by declaring and using a variable for Location, which creates a more permanent allocation for the Point structure. The following example shows code that can replace the last statement of the preceding example.
Dim exitLocation as New System.Drawing.Point(140, exitButton.Location.Y) exitButton.Location = exitLocation
Error ID: BC30068
To correct this error
If the statement assigns a value to an expression, replace the expression with a single writable variable, property, or array element.
If the statement makes indirect access through a value type (usually a structure), create a variable to hold the value type.
Assign the appropriate structure (or other value type) to the variable.
Use the variable to access the property to assign it a value.