从字符串& quot;& quot;转换键入&＃39; Decimal&＃39;无效.......... [英] Conversion from string "" to type 'Decimal' is not valid..........

问题描述

<跨度风格= "颜色：＃666666;字体家庭： '的Segoe UI'，黑体，迦楼，Arial字体，无衬线;字体大小：14px的">我有这样的代码，它提供与错误"从字符串转换为十进制类型无效

Private Sub btnadd_Click（ByVal sender As System.Object，ByVal e As System.EventArgs）处理btnadd.Click

  &NBSP; &NBSP; &NBSP;如果txtbookID.Text.Length = 0或者txtauthor.Text.Length = 0或者是
  &NBSP; &NBSP; &NBSP; txttitle.Text.Length = 0或txtpurchaseprice.Text.Length = 0或者
  &NBSP; &NBSP; &NBSP; txtsaleprice.Text.Length = 0或txtinventory.Text.Length = 0然后

  &NBSP; &NBSP; &NBSP; &NBSP; &NBSP; MessageBox.Show（"请输入所有数据。"）

  &NBSP; &NBSP; &NBSP;否则

  &NBSP; &NBSP; &NBSP; &NBSP; &NBSP; MessageBox.Show（"系统会将新记录存储到数据库中。"）
  &NBSP; &NBSP; &NBSP; &NBSP; &NBSP; btnclear.PerformClick（）

  &NBSP; &NBSP; &NBSP; &NBSP; &NBSP; lblnumberofrecords.Text = lblnumberofrecords.Text（）



$
  &NBSP; &NBSP; &NBSP; &NBSP; &NBSP;暗淡abookID作为新clsBook（txtbookID.Text，txtauthor.Text，txttitle.Text，CDEC（txtpurchaseprice.Text），

&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP ;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP; CDEC（txtsaleprice.Text），CINT（txtinventory.Text））



  &NBSP; &NBSP; &NBSP; &NBSP; &NBSP; lblnumberofrecords.Text = books.Count

  &NBSP; &NBSP; &NBSP; &NBSP; &NBSP; MessageBox.Show（"添加到数据库的记录"。）

  &NBSP; &NBSP; &NBSP; &NBSP; &NBSP; btnclear.PerformClick（）

Private Sub btnadd_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnadd.Click
        If txtbookID.Text.Length = 0 Or txtauthor.Text.Length = 0 Or
        txttitle.Text.Length = 0 Or txtpurchaseprice.Text.Length = 0 Or
        txtsaleprice.Text.Length = 0 Or txtinventory.Text.Length = 0 Then
            MessageBox.Show("Please enter all data.")
        Else
            MessageBox.Show("The system will store the new record into the database.")
            btnclear.PerformClick()
            lblnumberofrecords.Text = lblnumberofrecords.Text()


            Dim abookID As New clsBook(txtbookID.Text, txtauthor.Text, txttitle.Text, CDec(txtpurchaseprice.Text),
                                       CDec(txtsaleprice.Text), CInt(txtinventory.Text))

            lblnumberofrecords.Text = books.Count
            MessageBox.Show("records added to the database.")
            btnclear.PerformClick()

推荐答案

b $ b

 Dim abookID As New clsBook 
  (txtbookID.Text, txtauthor.Text, txttitle.Text, 
   CDec(txtpurchaseprice.Text), CDec(txtsaleprice.Text), 
   CInt(txtinventory.Text))

。您正在使用CDEC对一些数字值转换为十进制。

我想[txtpurchaseprice]，[txtsaleprice]或[txtinventory ]具有无法转换为十进制的值。



在使用[abookID]之前，您需要检查这些控件的值是否可以转换为十进制。 />


问候，

You are using CDEC for converting some numeric value to Decimal.
I suppose [txtpurchaseprice], [txtsaleprice], or [txtinventory] has a value that cannot be converted to Decimal.

You need to check if value of these controls can be converted into Decimal, before using [abookID].

Regards,

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