vb.net 如果文本框为空，则在数据库中写入 Null
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Write Null in Database if the TextBoxes are Empty
提问by Kristian Hernan C. Manuel
All I want to do is to insert Null with the database when the textbox is empty.
我想要做的就是在文本框为空时将 Null 与数据库一起插入。
--ACCOUNT
AS
BEGIN
-- SET NOCOUNT ON added to prevent extra result sets from
-- interfering with SELECT statements.
SET NOCOUNT ON;
SET IDENTITY_INSERT account ON
INSERT INTO dbo.account
(
AccntID ,
managedby ,
AccountHolder ,
Description ,
AccountType ,
ContactPerson ,
ContactNumber ,
EmailAddress ,
Address ,
ClientTYpe ,
SchemeType ,
SalesManager ,
DateCreated ,
Login ,
Password ,
Balance ,
FilterOption ,
Enable22 ,
AllowExtendedConfig
)
-- Insert statements for procedure here
VALUES (@AccntID, @managedby, @AccountHolder, @Description, @AccountType, @ContactPerson, @ContactNumber, @EmailAddress, @Address, @ClientType, @SchemeType, @SalesManager, @DateCreated, @Login, @Password, @Balance, @FilterOption, @Enable22, @AllowExtendedConfig)
SET IDENTITY_INSERT account OFF
END
What is the best way to add NULL values to the database when my textboxes are empty
当我的文本框为空时，将 NULL 值添加到数据库的最佳方法是什么
采纳答案by Parag Meshram
Set up helper functions such as:
设置辅助函数，例如：
Public Function DbNullOrStringValue(ByVal value As String) As Object
If String.IsNullOrEmpty(value) Then
Return DBNull.Value
Else
Return value
End If
End Function
And so the first code block would be simplified by calling it thus:
所以第一个代码块可以通过这样调用来简化：
Cmd.Parameters.AddWithValue("@AccntID", DbNullOrStringValue(TextBox1.Text))
Cmd.Parameters.AddWithValue("@managedby", DbNullOrStringValue(TextBox2.Text))
Cmd.Parameters.AddWithValue("@AccountHolder", DbNullOrStringValue(TextBox3.Text))
Cmd.Parameters.AddWithValue("@Description", DbNullOrStringValue(TextBox4.Text))
Cmd.Parameters.AddWithValue("@AccountType", DbNullOrStringValue(TextBox5.Text))
Cmdis your SqlCommanadobject
Cmd是你的SqlCommanad对象
回答by Minus
Consider something lighter than a new method :
考虑一些比新方法更轻的东西：
Cmd.Parameters.AddWithValue("@AccntID", IIF(String.IsNullOrEmpty(TextBox1.Text), DBNull.Value, TextBox1.Text))
But for the rest, use a SqlDataAdapteras suggested before.
但对于其余部分，请SqlDataAdapter按照之前的建议使用 a 。
回答by Farfarak
In the stored procedure you can use following:
在存储过程中，您可以使用以下内容：
Assumption: parameter name is @TextData
假设：参数名称是@TextData
NULLIF(LTRIM(RTRIM(@TextData)),'')
It will return NULL if @TextData = ''.
如果@TextData = ''，它将返回NULL。
回答by Hyman Gajanan
The best way will be to inherited text box and add additional functionality to it
最好的方法是继承文本框并为其添加附加功能
Public Class MyText
Inherits TextBox
'Either change default text property (but this will bug you while comparing text property)
Public Overrides Property Text() As String
Get
Return MyBase.Text
End Get
Set(ByVal value As String)
MyBase.Text = value
End Set
End Property
'Best way will be to write new property to use in sql query
Public ReadOnly Property TextSQL() As String
Get
If Me.Text = String.Empty Then
Return "NULL"
Else
Return Me.Text
'Return "'" & Me.Text & "'" 'or this
End If
End Get
End Property
End Class
now use this text box in your application
现在在您的应用程序中使用此文本框
cmd.Parameters.AddWithValue("@accountholder", txt_accHolder.TextSQL)
