C# 如何在txt输出期间仅选择现金并删除支票选项

我能得到一些帮助吗。我有一个如下所示的查询。现在它显示支票和现金。但我希望它只显示现金查询。是的，我相信我可以编辑它现在它容易受到SQL注入的攻击

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Data.SqlClient;


namespace MyTestData
{
public partial class frmCollection : Form
{
    public frmCollection()
    {
        InitializeComponent();
    }


    private void dtpFrom_ValueChanged(object sender, EventArgs e)
    {

    }

    private void btnExtract_Click(object sender, EventArgs e)
    {

        SqlConnection objConn = new SqlConnection("MYCONNECTION STRING ETCETC");


        SqlCommand objCmd = new SqlCommand("SELECT CONVERT(char(10),PaidDate,3)
 AS PaidDate,InvoiceNo,PayerCode,CollectedFee,
( CASE ReceiptTypeID WHEN 'Cash' THEN 'CASH' WHEN 'Check' THEN 'CHEQUE' END ) 
AS ReceiptTypeID FROM InvoicePayment 
WHERE (PaidDate >= CONVERT(datetime, '" + dtpFrom.Text + "', 105)) AND (PaidDate <= CONVERT(datetime, '" + dtpTo.Text + "', 105))", objConn);

        SqlDataReader objReader;
        objReader = objCmd.ExecuteReader();

        System.IO.FileStream fs = new System.IO.FileStream("C:\\CMSExportedData\\Collection-" + DateTime.Now.ToString("dd-MM-yyyy") + ".txt", System.IO.FileMode.Create);
        System.IO.StreamWriter sw = new System.IO.StreamWriter(fs, System.Text.Encoding.Default);

        int count = 0;
        while (objReader.Read())
        {

            for (int i = 0; i < 5; i++)
            {
                if (!objReader.IsDBNull(i))
                {
                    string s;
                    s = objReader.GetDataTypeName(i);
                    //MessageBox.Show(s);
                    if (objReader.GetDataTypeName(i) == "char")
                    {
                        sw.Write(objReader.GetString(i));
                    }
                    else if (objReader.GetDataTypeName(i) == "money")

                    {
                        sw.Write(objReader.GetSqlMoney(i).ToString());
                    }
                    else if (objReader.GetDataTypeName(i) == "nvarchar")
                    {
                        sw.Write(objReader.GetString(i));
                    }
                    else if (objReader.GetDataTypeName(i) == "varchar")
                    {
                        sw.Write(objReader.GetString(i));
                    }

                }
                if (i < 4)
                {
                    sw.Write("\t");
                }

            }
            count = count + 1;
            sw.WriteLine();

        }
        sw.Flush();
        fs.Close();
        objReader.Close();
        objConn.Close();
        MessageBox.Show(count + " records exported successfully.");
        this.Close();

    }

    private void frmCollection_Load(object sender, EventArgs e)
    {

    }

    private void dtpFrom_ValueChanged_1(object sender, EventArgs e)
    {

    }
}

}

编辑：以下是表格结构：

以下是一些示例数据：

SqlCommand objCmd = new SqlCommand("SELECT CONVERT(char(10),PaidDate,3) AS PaidDate,InvoiceNo,PayerCode,CollectedFee FROM InvoicePayment WHERE (PaidDate >= CONVERT(datetime, '" + dtpFrom.Text + "', 105)) AND (PaidDate <= CONVERT(datetime, '" + dtpTo.Text + "', 105)) AND ReceiptTypeID = 'Cash'", objConn);

请注意，我是如何删除case以显示其类型的，并在WHERE语句中添加了一个子句

还要尽量避免查询中的字符串连接，这会使您容易受到SQL注入的影响。尝试使用以下参数：

SqlCommand objCmd = new SqlCommand("SELECT CONVERT(char(10),PaidDate,3) AS PaidDate,InvoiceNo,PayerCode,CollectedFee FROM InvoicePayment WHERE (PaidDate >= CONVERT(datetime, @PAIDDATEFROM, 105)) AND (PaidDate <= CONVERT(datetime, @PAIDDATETO, 105)) AND ReceiptTypeID = 'Cash'", objConn);

SqlCommand.Parameters.Add("@PAIDDATEFROM", SqlDbType.DateTime).Value = dtpFrom.Text;
SqlCommand.Parameters.Add("@PAIDDATETO", SqlDbType.DateTime).Value = dtpTo.Text;

我只想看到现金

然后从大小写表达式中删除“Check”和“Check”，如下所示：

SELECT 
  CONVERT(char(10),PaidDate,3) AS PaidDate,InvoiceNo,
  PayerCode, CollectedFee, 
  (CASE ReceiptTypeID 
     WHEN 'Cash'  THEN 'CASH'  
  END ) AS ReceiptTypeID 
...

更新：

---

你的代码容易受到SQL注入攻击。是的，先生，我明白。这只是一个测试SQL。您好，先生，我尝试过您的方法，但它显示了一个空的地方，以前他们是支票。您好，我已经编辑它的样本数据。回答你的问题。我根本不想让它显示支票。即使有支票，我也不希望它出现在txt中。只是现金。@Newbie抱歉，我需要查看一些表格中的示例数据，而不是您正在使用的代码，请向我展示表格中的一些行以及查询后的外观。对不起，我不知道我如何在这里添加图片显示给你。我已经链接了一个外部链接供您参考sirHi，我已经添加了示例数据。谢谢你，先生，这很有帮助。

SELECT 
  CONVERT(char(10), PaidDate,3) AS PaidDate,
  InvoiceNo, CollectedFee, upper(ReceiptTypeID) AS ReceiptTypeID 
FROM @Invoices 
WHERE (PaidDate >= CONVERT(datetime, '20010101', 105))
  AND (PaidDate <= CONVERT(datetime, '20120101', 105))
  AND ReceiptTypeID IS NOT NULL
  AND lower(ReceiptTypeID) <> 'cheque'