Procedure returns error: Cannot cast System.Int32 to System.Int32[]

Question

我写了一个程序，应该 return 我的数据库中的一个值。要 returned 的值是一个整数。这是我的代码：

    Private Sub btnSelectProducts_Click(sender As Object, e As EventArgs) Handles btnSelectProducts.Click

    Try

    'Connection Variables
    Dim cnn As SqlCeConnection
    Dim connectionString As String

    'Connect to database
    connectionString = "Data Source=|DataDirectory|\Database\ContactsAndInventory.sdf"
    cnn = New SqlCeConnection(connectionString)

    Dim Stream As New MemoryStream()
    cnn.Open()

    Dim command As New SqlCeCommand("SELECT CATEGORY_ID FROM PRODUCT_CATEGORY WHERE (CATEGORY_NAME = @CATEGORY_NAME)", cnn)
    command.Parameters.AddWithValue("@CATEGORY_NAME", txtCategoryName.Text)

        Dim catId As Integer() = CType(command.ExecuteScalar(), Integer())'Error Here

    MsgBox(catId)

        cnn.Close()

    Catch ex As Exception

        MsgBox(ex.ToString)

    End Try


End Sub

我收到错误：

System.InvalidCastException: Unable to cast objct to type System.Int32 to type System.Int32[]

不知道为什么，该字段是一个整数字段，而我尝试 return 的值是一个整数。我做错了什么？

Answer 1

我发现我的错误：

  Dim catId = Convert.ToInt32(command.ExecuteScalar())

Procedure returns error: Cannot cast System.Int32 to System.Int32[]

Procedure returns error: Cannot cast System.Int32 to System.Int32[]

vb.net

sql-server-ce