Question

当包含Convert.ToInt32（cmd.ExecuteScalar（））时，我收到有关将nvarchar转换为int的错误

然而 - 我正在为它做的值被声明为INT，在我的存储过程中用作INT，并且是数据库中的INT。我不知道从

获取nvarchar的位置

input

存储过程是......

Protected Sub btnCreateAudition_Click(sender As Object, e As EventArgs) Handles btnCreateAudition.Click


    Protected Sub btnCreateAudition_Click(sender As Object, e As EventArgs) Handles btnCreateAudition.Click

        Dim audition_ID As Integer = 0
        Dim audition_Status As Integer = 0
        Dim ins_ID As Integer = DropDownList1.SelectedValue
        Dim ins_name As String = GetIns_Name(DropDownList1.SelectedValue)
        Dim judge1 As Integer = DropDownList2.SelectedValue
        Dim judge2 As Integer = DropDownList3.SelectedValue
        Dim judge3 As Integer = DropDownList4.SelectedValue
        Dim judge4 As Integer = DropDownList5.SelectedValue
        Dim judge5 As Integer = DropDownList6.SelectedValue
        Dim judgename1 As String = DropDownList2.SelectedValue
        Dim judgename2 As String = DropDownList3.SelectedValue
        Dim judgename3 As String = DropDownList4.SelectedValue
        Dim judgename4 As String = DropDownList5.SelectedValue
        Dim judgename5 As String = DropDownList6.SelectedValue
        Dim auditionIDTest As Integer = 100001
        Using con As New SqlConnection("Data Source=(LocalDB)\MSSQLLocalDB;AttachDbFilename=|DataDirectory|\BandDatabase.mdf;Integrated Security=True")
            Using cmd As New SqlCommand("Create_Audition")
                Using sda As New SqlClient.SqlDataAdapter()
                    cmd.CommandType = CommandType.StoredProcedure
                    cmd.Parameters.AddWithValue("@audition_date", Calendar1.SelectedDate)
                    cmd.Parameters.AddWithValue("@audition_location", txtauditionlocation.Text)
                    cmd.Parameters.AddWithValue("@audition_status", audition_Status)
                    cmd.Parameters.AddWithValue("@instrument_name", ins_name)
                    cmd.Parameters.AddWithValue("@ins_ID", ins_id)
                    cmd.Parameters.AddWithValue("@judge1", judge1)
                    cmd.Parameters.AddWithValue("@judge2", judge2)
                    cmd.Parameters.AddWithValue("@judge3", judge3)
                    cmd.Parameters.AddWithValue("@judge4", judge4)
                    cmd.Parameters.AddWithValue("@judge5", judge5)
                    cmd.Parameters.AddWithValue("@judgename1", judgename1)
                    cmd.Parameters.AddWithValue("@judgename2", judgename2)
                    cmd.Parameters.AddWithValue("@judgename3", judgename3)
                    cmd.Parameters.AddWithValue("@judgename4", judgename4)
                    cmd.Parameters.AddWithValue("@judgename5", judgename5)
                    cmd.Parameters.AddWithValue("@audition_IDTest", auditionIDTest)
                    cmd.Connection = con
                    con.Open()
                    'No error if below line is commented out, but DB isn't updated
                    audition_ID = Convert.ToInt32(cmd.ExecuteScalar())
                    con.Close()
                End Using
            End Using
        End Using
    End Sub

哪里可能将audition_ID指定为nvarchar类型？

Answer 1

我看到你在这里声明instrument_name参数为整数：

CREATE PROCEDURE [dbo].[Create_Audition]
...
@instrument_name INT,
...

但您使用以下代码行将值传递为字符串：

' declaration
Dim ins_name As String = GetIns_Name(DropDownList1.SelectedValue)

' in SqlCommand parameters
' this passing a string to an int SQL parameter, hence conversion failed
cmd.Parameters.AddWithValue("@instrument_name", ins_name)

由于instrument_name预计为字符串，因此请将其数据类型更改为nvarchar，然后您的查询应该有效：

CREATE PROCEDURE [dbo].[Create_Audition]
    ...
    @instrument_name NVARCHAR,
    ...

...

在Convert.ToInt32（cmd.ExecuteScalar（））中将数据类型nvarchar转换为int时出错

1 个答案: