Question

我正在使用Visual Studio .NET 2003，当所有文本框，组合框字段都填充数据时，添加按钮工作正常，但是在测试未填充数据的字段时将其保留为NULL，则返回错误说“字符串未被识别为有效日期时间“

我有一个名为txtPurchasedDate的文本框

我的存储过程

 CREATE PROCEDURE AddOfficeEquipmentProfile
    (
    @OE_ID      varchar(11)     =   NULL,
    @OE_Category        char(3)         =   NULL,
    @OE_SubCategory char(3)         =   NULL,
    @OE_Name        varchar(35)     =   NULL,
    @OE_User        varchar(35)     =   NULL,
    @OE_Brand       varchar(15)     =   NULL,
    @OE_Model       varchar(35)     =   NULL,
    @OE_Specs       varchar(1000)       =   NULL,
    @OE_SerialNo        varchar(35)     =   NULL,
    @OE_PropertyNo  varchar(35)     =   NULL,
    @OE_MacAddress  varchar(100)        =   NULL,   
    @OE_Static_IP       varchar(15)     =   NULL,
    @OE_Vendor      varchar(35)     =   NULL,
    @OE_PurchaseDate    smalldatetime       =   NULL,
    @OE_WarrantyInclusiveYear   int     =   NULL,
    @OE_WarrantyStatus  char(2)         =   NULL,
    @OE_Status      varchar(15)     =   NULL,
    @OE_Dept_Code   char(3)         =   NULL,
    @OE_Location_Code   char(8)         =   NULL,
    @OE_Remarks     varchar(1000)       =   NULL
    )
    AS

    INSERT INTO tblOfficeEquipmentProfile (OE_ID, OE_Category, OE_SubCategory, OE_Name, OE_User, OE_Brand, OE_Model, OE_Specs, OE_SerialNo,
    OE_PropertyNo, OE_MacAddress, OE_Static_IP, OE_Vendor, OE_PurchaseDate, OE_WarrantyInclusiveYear, OE_WarrantyStatus, OE_Status, OE_Dept_Code,
    OE_Location_Code, OE_Remarks ) 
    VALUES (@OE_ID, @OE_Category, @OE_SubCategory, @OE_Name, @OE_User, @OE_Brand, @OE_Model, 
    @OE_Specs, @OE_SerialNo, @OE_PropertyNo, @OE_MacAddress, @OE_Static_IP, @OE_Vendor, @OE_PurchaseDate, @OE_WarrantyInclusiveYear, @OE_WarrantyStatus,
    @OE_Status, @OE_Dept_Code, @OE_Location_Code, @OE_Remarks)

    IF @@ERROR<>0
        BEGIN
            ROLLBACK TRANSACTION
            RETURN 0
        END 
    ELSE
        BEGIN
            COMMIT TRANSACTION
            RETURN 1
        END
    GO

我的Vb.net添加按钮代码

 Dim cmd As SqlCommand = sqlconn.CreateCommand
        sqlconn.Open()
        cmd.CommandType = CommandType.StoredProcedure
        cmd.CommandText = "AddOfficeEquipmentProfile"

    cmd.Parameters.Add("@OE_ID", SqlDbType.VarChar, 11, "oeq-su-999")
    cmd.Parameters.Add("@OE_Category", SqlDbType.Char, 3, "COM")
    cmd.Parameters.Add("@OE_SubCategory", SqlDbType.Char, 3, "SU")
    cmd.Parameters.Add("@OE_Name", SqlDbType.VarChar, 35, "adminpmis01")
    cmd.Parameters.Add("@OE_User", SqlDbType.VarChar, 35, "Ivan")
    cmd.Parameters.Add("@OE_Brand", SqlDbType.VarChar, 15, "DELL")
    cmd.Parameters.Add("@OE_Model", SqlDbType.VarChar, 35, "optiplex")
    cmd.Parameters.Add("@OE_Specs", SqlDbType.VarChar, 1000, "dualcore")
    cmd.Parameters.Add("@OE_SerialNo", SqlDbType.VarChar, 35, "sgh5960")
    cmd.Parameters.Add("@OE_PropertyNo", SqlDbType.VarChar, 35, "j7h7h6g6f2")
    cmd.Parameters.Add("@OE_MacAddress", SqlDbType.VarChar, 100, "j7h7:h6g6f2")
    cmd.Parameters.Add("@OE_Static_IP", SqlDbType.VarChar, 15, "192.168.1.5")
    cmd.Parameters.Add("@OE_Vendor", SqlDbType.VarChar, 35, "ADWAYS")

    cmd.Parameters.Add("@OE_PurchaseDate", SqlDbType.SmallDateTime)
    cmd.Parameters.Add("@OE_WarrantyInclusiveYear", SqlDbType.Int)
    cmd.Parameters.Add("@OE_WarrantyStatus", SqlDbType.Char, 2, "IN")
    cmd.Parameters.Add("@OE_Status", SqlDbType.VarChar, 15, "Good")
    cmd.Parameters.Add("@OE_Dept_Code", SqlDbType.Char, 3, "ADM")
    cmd.Parameters.Add("@OE_Location_Code", SqlDbType.Char, 8, "ADM_OFC")
    cmd.Parameters.Add("@OE_Remarks", SqlDbType.VarChar, 1000, "ACTIVE")
    cmd.Parameters("@OE_ID").Value = txtOEID.Text
    cmd.Parameters("@OE_Category").Value = cmbCategory.Text
    cmd.Parameters("@OE_SubCategory").Value = cmbSubCategory.Text
    cmd.Parameters("@OE_Name").Value = txtName.Text
    cmd.Parameters("@OE_User").Value = txtUser.Text
    cmd.Parameters("@OE_Brand").Value = cmbBrand.Text
    cmd.Parameters("@OE_Model").Value = cmbModel.Text
    cmd.Parameters("@OE_Specs").Value = txtSpecs.Text
    cmd.Parameters("@OE_SerialNo").Value = txtSerialNo.Text
    cmd.Parameters("@OE_PropertyNo").Value = txtPropertyNo.Text
    cmd.Parameters("@OE_MacAddress").Value = txtMacAddress.Text
    cmd.Parameters("@OE_Static_IP").Value = txtStaticIp.Text
    cmd.Parameters("@OE_Vendor").Value = txtVendor.Text
    cmd.Parameters("@OE_PurchaseDate").Value = txtPurchaseDate.Text
    cmd.Parameters("@OE_WarrantyInclusiveYear").Value = txtWarrantyInclusiveYear.Text
    cmd.Parameters("@OE_WarrantyStatus").Value = txtWarrantyStatus.Text
    cmd.Parameters("@OE_Status").Value = txtStatus.Text
    cmd.Parameters("@OE_Dept_Code").Value = cmbDeptCode.Text
    cmd.Parameters("@OE_Location_Code").Value = cmbLocationCode.Text
    cmd.Parameters("@OE_Remarks").Value = txtRemarks.Text
    cmd.ExecuteNonQuery()
    MsgBox("Successfully Added Equipment Profile")
    sqlconn.Close()

Answer 1

如果要存储空值，则必须在vb代码中使用条件逻辑，以便不将这些参数发送到存储过程，或者发送dbnull值。甚至你的char字段都存储空字符串，这可能不是你的意图。

Answer 2

使用

If (Not String.IsNullOrEmpty(txtPurchaseDate.Text)) Then
    cmd.Parameters("@OE_PurchaseDate").Value = txtPurchaseDate.Text
End If

Answer 3

为什么不在你的PurchaseDate中使用DateTimePicker而不是txtPurchaseDate.Text中的文本框，你可以命名你的控件dtpPurchaseDate然后你有：

cmd.Parameters("@OE_PurchaseDate").Value = dtpPurchaseDate.Value

DateTime Picker的默认值（或最小值）是1/1/1980，因此您可以将dtpPurchaseDate的值初始化为1/1/1980，如：

dtpPurchaseDate = System.DateTime.Parse("1/1/1980")

因此，这意味着当存储在数据库中时，它的值为1/1/1980而不是NULL。

如果您想要使用文本框，那么您可以检查是否为空，然后分配最小日期值，实际上是1/1/0001，如下所示：

If (If (String.IsNullOrEmpty(txtPurchaseDate.Text)) Then
   cmd.Parameters("@OE_PurchaseDate").Value = DBNull.Value  
Else
   Dim tempPurchaseDate as DateTime

   System.DateTime.TryParse(txtPurchaseDate.Text, tempPurchaseDate)
   cmd.Parameters("@OE_PurchaseDate").Value = tempPurchaseDate         
End If

但它再次在数据库中有一个存储值为1/1/0001

您可以在TextBox中将其显示为空，如：鉴于您有一个名为dr

的DataRow

If (dr["OE_PurchaseDate"] = System.DateTime.Parse("1/1/0001")) Then
   txtPurchaseDate.Text = ""
Else
   txtPurchaseDate.Text = dr["OE_PurchaseDate"]
End If

允许Null值保存在数据库中

3 个答案: