c# - 如何使用参数转换为正确的数据类型。使用 SQL 查询？

Question

我正在尝试将一些值保存到 MS SQL 中的数据表中，但数据类型存在一些问题。我需要使用参数将这些值转换为正确的数据类型

这是我的桌子,,,

表格图片

这是我用来向数据库传递值的代码，我需要使用参数来转换数据，请帮我做......

private void InsertRec(StringCollection sc)
    {
        var conn = new SqlConnection(GetConnectionString());
        var sb = new StringBuilder(string.Empty);
        var splitItems = (string[])null;
        foreach (string item in sc)
        {
            const string sqlStatement =
                "INSERT INTO DEL_PurchasesLines1 (DealerCode,InvoiceNo,InvoiceDate,ItemIdentityCode,PurchasingPrice,DiscountRate,Discount,IssueMode,Qty,Total,ExpireDate,BatchNumber,UploadedStatus,InsertedDate,UploadedDate,Force,Principle,NewTotal) VALUES";

            if (item.Contains(","))
            {
                splitItems = item.Split(",".ToCharArray());
                sb.AppendFormat("{0}('{1}','{2}','{3}','{4}','{5}','{6}','{7}','{8}','{9}','{10}','{11}','{12}','{13}','{14}','{15}','{16}','{17}','{18}'); ", sqlStatement, splitItems[0], splitItems[1], splitItems[2], splitItems[3], splitItems[4], splitItems[5], splitItems[6], splitItems[7], splitItems[8], splitItems[9], splitItems[10], splitItems[11], splitItems[12], splitItems[13], splitItems[14], splitItems[15], splitItems[16], splitItems[17]);
            }
        }

        try
        {
            conn.Open();
            SqlCommand cmd = new SqlCommand(sb.ToString(), conn) { CommandType = CommandType.Text };
            cmd.ExecuteNonQuery();

            Page.ClientScript.RegisterClientScriptBlock(typeof(Page), "Script", "alert('Records Successfuly Saved!');", true);

        }
        catch (System.Data.SqlClient.SqlException ex)
        {
            string msg = "Insert Error:";
            msg += ex.Message;
            throw new Exception(msg);
        }
        finally
        {
            conn.Close();
        }
    }

这就是我将值输入查询的方式。

    protected void btnSaave_Click(object sender, EventArgs e)
    {
        int rowIndex = 0;
        StringCollection sc = new StringCollection();
        if (ViewState["CurrentData"] != null)
        {
            DataTable dtCurrentTable = (DataTable)ViewState["CurrentData"];
            DataRow drCurrentRow = null;
            if (dtCurrentTable.Rows.Count > 0)
            {
                for (int i = 1; i <= dtCurrentTable.Rows.Count; i++)
                {
                    var dtDealerCode = txtIDealerCode.Text;
                    var dtInvoiceNo = txtInvoiceNumber.Text;
                    var dtInvoiceDate = txtInvoiceDate.Text;
                    var dtItemIdentityCode = (Label)GridView1.Rows[rowIndex].Cells[1].FindControl("ItemCode");
                    var dtPurchasingPrice = (Label)GridView1.Rows[rowIndex].Cells[3].FindControl("UnitPrice");
                    var dtDiscountRate = txtDiscount.Text;
                    var dtDiscount = txtProductDiscount.Text;
                    var dtIssueMode = ddlIssueMode.SelectedValue;
                    var dtQty = (Label)GridView1.Rows[rowIndex].Cells[6].FindControl("Quantity");
                    var dtTotal = (Label)GridView1.FooterRow.FindControl("GetTotal");
                    var dtExpireDate = (Label)GridView1.Rows[rowIndex].Cells[5].FindControl("ExpiaryDate");
                    var dtBatchNumber = (Label)GridView1.Rows[rowIndex].Cells[4].FindControl("Batch");
                    var dtUploadedStatus = txtInvoiceDate.Text;
                    var dtInsertedDate = "1";
                    var dtUploadedDate = txtInvoiceDate.Text;
                    var dtForce = txtForce.Text;
                    var dtPrinciple = txtPrinciple.Text;
                    var NewTotal = (Label)GridView1.FooterRow.FindControl("GetQuantity");

                    sc.Add(dtDealerCode + "," + dtInvoiceNo + "," + dtInvoiceDate + "," + dtItemIdentityCode.Text + "," + dtPurchasingPrice.Text + "," + dtDiscountRate + "," + dtDiscount + "," + dtIssueMode + "," + dtQty.Text + "," + dtTotal.Text + "," + dtExpireDate + "," + dtBatchNumber.Text + "," + dtUploadedStatus + "," + dtInsertedDate + "," + dtUploadedDate + "," + dtForce + "," + dtPrinciple + "," + dtPrinciple + "," + NewTotal.Text);
                    rowIndex++;
                }

                InsertRec(sc);
            }
        }
    }

Answer 1

这是一些令人讨厌的代码。我不知道您是否是编程新手，但您应该为此使用存储过程，其中该过程定义了需要作为参数传入的 14 个左右的参数。这将指导您的代码，以便您为参数化存储过程调用添加参数，每个参数都需要强类型，这将指导您为表的每个列值进行正确的转换。您还应该创建一个 C# 类，将所有表列值定义为公共属性。请原谅 VB.NET，但您将通过这个简单的数据访问层 (DAL) 示例片段了解这个想法，UpdateOffer 可以重命名为 AddUpdateOffer，这可以通过将记录 id 传递给 AddUpdate 来检查记录是否存在存储过程，如果是更新，

 Public Class Offer

        Public OfferID As Integer
        Public PropertyID As Integer
        Public AgentUserID As Integer
        Public AgentName As String
        Public BuyerUserID As Integer
        Public BuyerName As String
        Public BuyerType As String
        Public Offer As Integer
        Public NetOffer As Integer
        Public ClosingCost As Integer
        Public Allowances As Integer
        Public RepairCosts As Integer
        Public TotalCredits As Integer
        Public OfferType As String
        Public OfferDate As String
        Public ProxyOffer As Integer
        Public NetProxyOffer As Integer
        Public ResultResponse As SUBMIT_OFFER_RESULT
        'Public ResultAcceptedOffer As Integer
        Public ResultAcceptedNetOffer As Integer
        'Public ResultHighestOffer As Integer
        Public ResultHighestNetOffer As Integer
        Public Notifications As ArrayList = New ArrayList
        Public EarnestMoneyDeposit As Integer
        Public DownPayment As Integer
        Public TypeOfFinancing As String
        Public OfferStatus As String
        Public Note As String
        Public Visble As Boolean = True
        Public OfferStatusChangedDate As DateTime
        Public EstimatedCloseDate As DateTime
        Public SourceType As String

        Public Sub GetOffer(ByVal offerID As Integer)

            Dim offerDB As OSP.DataAccess.OfferDB = New OSP.DataAccess.OfferDB
            Dim rs As SqlClient.SqlDataReader
            rs = offerDB.GetOffer(offerID)
            Do While rs.Read
                Me.OfferID = offerID
                Me.PropertyID = rs("PROPERTY_ID")
                Me.AgentUserID = rs("AGENT_USER_ID")
                Me.BuyerUserID = IIf(IsDBNull(rs("BUYER_USER_ID")), 0, rs("BUYER_USER_ID"))
                Me.Offer = rs("OFFER")
                Me.NetOffer = rs("NET_OFFER")
                Me.TotalCredits = rs("TOTAL_CREDITS")
                Me.ProxyOffer = rs("PROXY_OFFER")
                Me.OfferType = rs("OFFERTYPE")
                Me.OfferDate = rs("OFFER_DATE")
                Me.DownPayment = IIf(IsDBNull(rs("DOWN_PAYMENT")), 0, rs("DOWN_PAYMENT"))
                Me.EarnestMoneyDeposit = IIf(IsDBNull(rs("EARNEST_MONEY_DEPOSIT")), 0, rs("EARNEST_MONEY_DEPOSIT"))
                Me.TypeOfFinancing = rs("TYPE_OF_FINANCING")
                Me.BuyerName = GlobalFunctions.DefaultString(rs("BUYER_NAME"))
                Me.BuyerType = GlobalFunctions.DefaultString(rs("BUYER_TYPE"))
                Me.AgentName = rs("OFFER_BY_NAME")
                Me.OfferStatus = GlobalFunctions.DefaultString(rs("OFFER_STATUS"))
                Me.Note = GlobalFunctions.DefaultString(rs("NOTE"))
                Me.OfferStatusChangedDate = IIf(IsDBNull(rs("OFFER_STATUS_CHANGED_DATE")), Me.OfferStatusChangedDate, rs("OFFER_STATUS_CHANGED_DATE"))
                Me.Visble = IIf(IsDBNull(rs("VISIBLE")), True, rs("VISIBLE"))
                Me.EstimatedCloseDate = IIf(IsDBNull(rs("ESTIMATED_CLOSE_DATE")), DateTime.MinValue, rs("ESTIMATED_CLOSE_DATE"))
            Loop

            Try
                If Not rs.IsClosed Then
                    rs.Close() : rs = Nothing
                End If
                If Not offerDB Is Nothing Then
                    offerDB.Dispose() : offerDB = Nothing
                End If
            Catch : End Try

        End Sub

        Public Function UpdateOffer() As Integer

            Dim offerDB As OSP.DataAccess.OfferDB = New OSP.DataAccess.OfferDB
            Return offerDB.UpdateOffer(Me)

        End Function
End Class

 Public Class OfferDB
        Implements System.IDisposable


        Dim db As SQLDatabase

        Public Sub New()
            db = New SQLDatabase(GlobalSettings.GetDefaultConnectionString)
        End Sub

        Public Sub Dispose() Implements System.IDisposable.Dispose

            If Not db Is Nothing Then
                db = Nothing
            End If

        End Sub

  Public Function GetOffer(ByVal offerID As Integer) As SqlClient.SqlDataReader

            Dim dbCommand As DbCommand = db.GetStoredProcCommand("OSP_GET_OFFER")
            db.AddInParameter(dbCommand, "@OFFER_ID", SqlDbType.Int, offerID)

            Try
                Return db.ExecuteReader(dbCommand)
            Catch ex As Exception
                Dim rethrow As Boolean = ExceptionPolicy.HandleException(ex, "EXCEPTION_CRITICAL")
                If (rethrow) Then
                    Throw
                End If
            End Try


        End Function


        Public Function UpdateOffer(ByVal offer As OSP.Offer) As Integer

            Dim dbCommand As DbCommand = db.GetStoredProcCommand("OSP_UPDATE_OFFER")

            db.AddInParameter(dbCommand, "@OFFER_ID", SqlDbType.Int, offer.OfferID)
            db.AddInParameter(dbCommand, "@BUYER_USER_ID", SqlDbType.Int, offer.BuyerUserID)
            db.AddInParameter(dbCommand, "@OFFER", SqlDbType.Int, offer.Offer)
            db.AddInParameter(dbCommand, "@TOTAL_CREDITS", SqlDbType.Int, offer.TotalCredits)
            db.AddInParameter(dbCommand, "@OFFER_TYPE", SqlDbType.VarChar, offer.OfferType)
            db.AddInParameter(dbCommand, "@OFFER_DATE", SqlDbType.VarChar, offer.OfferDate)
            db.AddInParameter(dbCommand, "@TYPE_OF_FINANCING", SqlDbType.VarChar, offer.TypeOfFinancing)
            db.AddInParameter(dbCommand, "@DOWN_PAYMENT", SqlDbType.Int, offer.DownPayment)
            db.AddInParameter(dbCommand, "@EARNEST_MONEY_DEPOSIT", SqlDbType.Int, offer.EarnestMoneyDeposit)
            db.AddInParameter(dbCommand, "@OFFER_STATUS", SqlDbType.VarChar, offer.OfferStatus)
            db.AddInParameter(dbCommand, "@NOTE", SqlDbType.VarChar, offer.Note)
            If Not offer.OfferStatusChangedDate = DateTime.MinValue Then
                db.AddInParameter(dbCommand, "@OFFER_STATUS_CHANGED_DATE", SqlDbType.DateTime, offer.OfferStatusChangedDate)
            End If

            Try
                Return db.ExecuteScalar(dbCommand)
            Catch ex As Exception
                Dim rethrow As Boolean = ExceptionPolicy.HandleException(ex, "EXCEPTION_CRITICAL")
                If (rethrow) Then
                    Throw
                End If
            End Try

        End Function
End Class

Answer 2

正确的方法是构建一个方法来请求它期望的特定值，或者通过为每个项目设置一个参数或通过一个类类型，即：

private void InsertRec(DEL_PurchasesLines1 lineToInsert)

您将创建的类在哪里DEL_PurchasesLines1（以表命名），或者这个：

private void InsertRec(string DealerCode,string InvoiceNo,DateTime InvoiceDate,
            string ItemIdentityCode,decimal PurchasingPrice, decimal DiscountRate,
            decimal Discount,string IssueMode,decimal Qty,decimal Total,
            DateTime ExpireDate,string BatchNumber,string UploadedStatus,
            string InsertedDate,DateTime UploadedDate,string Force,
            decimal Principle,decimal NewTotal)

FWIW，一个表中的许多列几乎总是意味着表设计有问题，但我暂时不理会它。使用第二种方法，您的按钮单击将如下所示：

protected void btnSave_Click(object sender, EventArgs e)
{
    if (ViewState["CurrentData"] == null) return;
    DataTable dtCurrentTable = (DataTable)ViewState["CurrentData"];
    if (dtCurrentTable.Rows.Count == 0) return;

    int rowIndex = 0;

    var dtDealerCode = txtIDealerCode.Text;
    var dtInvoiceNo = txtInvoiceNumber.Text;
    var dtInvoiceDate = DateTime.Parse(txtInvoiceDate.Text);
    var dtDiscountRate = decimal.Parse(txtDiscount.Text);
    var dtDiscount = decimal.Parse(txtProductDiscount.Text);
    var dtIssueMode = ddlIssueMode.SelectedValue;
    var dtUploadedStatus = DateTime.Parse(txtInvoiceDate.Text);
    var dtInsertedDate = "1"; //Really? 
    var dtUploadedDate = DateTime.Parse(txtInvoiceDate.Text);
    var dtForce = txtForce.Text;
    var dtPrinciple = decimal.Parse(txtPrinciple.Text);

    for (int i = 1; i <= dtCurrentTable.Rows.Count; i++)
    {
        var dtItemIdentityCode = (Label)GridView1.Rows[rowIndex].Cells[1].FindControl("ItemCode");
        var dtPurchasingPrice = decimal.Parse((Label)GridView1.Rows[rowIndex].Cells[3].FindControl("UnitPrice"));
        var dtQty = decimal.Parse((Label)GridView1.Rows[rowIndex].Cells[6].FindControl("Quantity"));
        var dtTotal = decimal.Parse((Label)GridView1.FooterRow.FindControl("GetTotal"));
        var dtExpireDate = DateTime.Parse((Label)GridView1.Rows[rowIndex].Cells[5].FindControl("ExpiaryDate"));
        var dtBatchNumber = (Label)GridView1.Rows[rowIndex].Cells[4].FindControl("Batch");
        var NewTotal = decimal.Parse((Label)GridView1.FooterRow.FindControl("GetQuantity"));

        InsertRec(dtDealerCode,dtInvoiceNo,dtInvoiceDate,dtItemIdentityCode,
            dtPurchasingPrice,dtDiscountRate,dtDiscount,dtIssueMode,dtQty,
            dtTotal,dtExpireDate,dtBatchNumber,dtUploadedStatus,dtInsertedDate,
            dtUploadedDate,dtForce,dtPrinciple,NewTotal);

        rowIndex++;
    }
}

将它们组合在一起，InsertRec()将如下所示：

private void InsertRec(string DealerCode,string InvoiceNo,DateTime InvoiceDate,
            string ItemIdentityCode,decimal PurchasingPrice, decimal DiscountRate,
            decimal Discount,string IssueMode,decimal Qty,decimal Total,
            DateTime ExpireDate,string BatchNumber,string UploadedStatus,
            string InsertedDate,DateTime UploadedDate,string Force,
            decimal Principle,decimal NewTotal)
{

    const string sqlStatement =
            "INSERT INTO DEL_PurchasesLines1 (" +
              "DealerCode,InvoiceNo,InvoiceDate,ItemIdentityCode,PurchasingPrice,DiscountRate,Discount,IssueMode,Qty,Total,ExpireDate,BatchNumber,UploadedStatus,InsertedDate,UploadedDate,Force,Principle,NewTotal" + 
            ") VALUES (" +
              "@DealerCode, @InvoiceNo, @InvoiceDate, @ItemIdentityCode, @PurchasingPrice, @DiscountRate, @Discount, @IssueMode, @Qty, @Total, @ExpireDate, @BatchNumber, @UploadSTatus, @InsertedDate, @UploadedDate, @Force, @Principle, @NewTotal" +
            ")";

    using (conn = new SqlConnection(GetConnectionString())
    using (cmd = new SqlCommand(sqlStatement, conn))
    {
        cmd.Parameters.Add("@DealerCode", SqlDbType.NVarChar, 10).Value = DealerCode;
        cmd.Parameters.Add("@InvoiceNo", SqlDbType.NVarChar, 10).Value = InvoiceNo;
        cmd.Parameters.Add("@InvoiceDate", SqlDbType.DateTime).Value = InvoiceDate;
        cmd.Parameters.Add("@ItemIdentityCode", SqlDbType.NVarChar, 10).Value = ItemIdentityCode;
        cmd.Parameters.Add("@PurchasingPrice", SqlDbType.Decimal).Value = PurchasingPrice;
        cmd.Parameters.Add("@DiscountRate", SqlDbType.Decimal).Value = DiscountRate;
        //...

        conn.Open();
        cmd.ExecuteNonQuery();
    }

    Page.ClientScript.RegisterClientScriptBlock(typeof(Page), "Script", "alert('Records Successfuly Saved!');", true);
}

多亏了一个叫做 Sql Injection 的小东西，你对 StringBuilder 和 Format 字符串所做的事情是完全不合适的。这很重要，所以你绝对应该阅读它。

我还看到您正在尝试将插入分组为一个批次。这很好，但多亏了连接池，它并没有真正让你受益。使用正确的查询参数化也更难。不过，这并非不可能，所以我现在将向您展示一个使用其他方法签名的示例，这样会更容易一些：

private void InsertRec(DEL_PurchasesLines1[] linesToInsert)
{
    const string sqlBase =
            "INSERT INTO DEL_PurchasesLines1 (" +
              "(DealerCode,InvoiceNo,InvoiceDate,ItemIdentityCode,PurchasingPrice,DiscountRate,Discount,IssueMode,Qty,Total,ExpireDate,BatchNumber,UploadedStatus,InsertedDate,UploadedDate,Force,Principle,NewTotal)" + 
            " VALUES ";

    const string valueBase = 
              "{0}(@DealerCode{1}, @InvoiceNo{1}, @InvoiceDate{1}, @ItemIdentityCode{1}, @PurchasingPrice{1}, @DiscountRate{1}, @Discount{1}, @IssueMode{1}, @Qty{1}, @Total{1}, @ExpireDate{1}, @BatchNumber{1}, @UploadSTatus{1}, @InsertedDate{1}, @UploadedDate{1}, @Force{1}, @Principle{1}, @NewTotal{1})";

    var sb = new StringBuilder(sqlBase);
    if (DEL_PurchasesLines1.Length > 1) sb.Append("(")
    var delimiter = "";
    for (int i = 0;i<DEL_PurchasesLines1.Length;i++)
    {
         sb.AppendFormat(valueBase, i, delimiter);
         delimiter = ",";
    }
    if (DEL_PurchasesLines1.Length > 1) sb.Append(")")

    using (conn = new SqlConnection(GetConnectionString())
    using (cmd = new SqlCommand(sqlStatement, conn))
    {

        for (int i = 0;i<DEL_PurchasesLines1.Length;i++)
        {
            cmd.Parameters.Add("@DealerCode" + i, SqlDbType.NVarChar, 10).Value = linesToInsert[i].DealerCode;
            cmd.Parameters.Add("@InvoiceNo" + i, SqlDbType.NVarChar, 10).Value = linesToInsert[i].InvoiceNo;
            cmd.Parameters.Add("@InvoiceDate + i", SqlDbType.DateTime).Value = linesToInsert[i].InvoiceDate;
            cmd.Parameters.Add("@ItemIdentityCode" + i, SqlDbType.NVarChar, 10).Value = linesToInsert[i].ItemIdentityCode;
            cmd.Parameters.Add("@PurchasingPrice" + i, SqlDbType.Decimal).Value = linesToInsert[i].PurchasingPrice;
            cmd.Parameters.Add("@DiscountRate" + i, SqlDbType.Decimal).Value = linesToInsert[i].DiscountRate;
        //...
        }
        conn.Open();
        cmd.ExecuteNonQuery();
    }
}