如何从数据库中选择日期并将所选值设置为datetimepicker [英] How to get selected date from database and set the selected value to datetimepicker

问题描述

我必须从数据库中获取日期值，并在使用dataReader时将所选值设置为我的datetimpicker。



[edit]已添加代码块 - OriginalGriff [/编辑]



我尝试过：

  public   void  loadVoucher（）
 {
 connection =  new  SqlConnection（DBHelper.ConnectionString（））; 
 connection.Open（）; 
 command =  new  SqlCommand（）; 
 command.Connection = connection; 
 command.CommandText =   select * from lease where linovice =' + txtLeaseVoucherNo.Text +  '; 
 da =  new  SqlDataAdapter（）; 
 da.SelectCommand = command; 
 ds =  new  DataSet（）; 
 da.Fill（ds）; 
 
 尝试 
 {
 
 
 reader2 = command.ExecuteReader（）; 
 {
  while （reader2.Read（））
 {
 
 txtName.Text =（reader2 [  client_name]。ToString（））; 
 txtcFname.Text =（reader2 [  f_name]。ToString（））; 
 txtCNIC.Text =（reader2 [  cnic]。ToString（））; 
 txtGName.Text =（reader2 [  g_name]。ToString（））; 
 txtGFname.Text =（reader2 [  g_fname]。ToString（））; 
 txtGCnic.Text =（reader2 [  g_cnic]。ToString（））; 
 txtGPhone.Text =（reader2 [  g_phone]。ToString（））; 
 txtGPhone2.Text =（reader2 [  g_phone2]。ToString（））; 
 txtGAdress.Text =（reader2 [  g_adress]。ToString（））; 
 txtGadress2.Text =（reader2 [  g_adress2]。ToString（））; 
 txtTotalBill.Text =（reader2 [  total_bill]。ToString（））; 
 txtAdvance.Text =（reader2 [  advance]。ToString（））; 
 txtPlan.Text =（reader2 [  lplan]。ToString（））; 
 txtLeaseAmount.Text =（reader2 [  lease_amu]。ToString（））; 
 txtInstalment.Text =（reader2 [  linstalment]。ToString（））; 
 txtSMName.Text =（reader2 [  sales_men]。ToString（））; 
 txtInspName.Text =（reader2 [  insp]。ToString（））; 
 comboBoxReceivedIn.Text =（reader2 [  GName]。ToString（））; 
 txtCurrentBal.Text =（reader2 [  balbefore]。ToString（））; 
 txtNewCurrentBal.Text =（reader2 [  balafter]。ToString（））; 
 DateTime datevalue; 
  if （DateTime.TryParse（reader2 [  startsfrom]。ToString（）， out  datevalue））
 {
 dateTimePickerStartsFrom.Value = datevalue; 
} 
 其他 
 {
  //  < span class =code-comment> TODO  - 转换失败...不是有效的日期时间 
  //  打印出来，看看它有什么问题......  
} 
 
 txtChecque.Text =（reader2 [  checqueNo]。ToString（））; 
 txtPageNo.Text =（reader2 [  pageNo]。ToString（））; 
 
 
} 
 
} 
} 
  catch （Exception ex） 
 {
  //   MessageBox.Show（ex.Message）;  
 
 
} 
 最后 
 {
 connection.Close（）; 
} 
 
} 

解决方案

首先，永远不要那样做！不要连接字符串以构建SQL命令。它让您对意外或故意的SQL注入攻击持开放态度，这可能会破坏您的整个数据库。改为使用参数化查询。

其次，为什么使用循环来检索数据？你总是将它加载到同一个地方，所以看起来很傻 - 最后一组值将始终是唯一显示的值。

第三，为什么要将数据库值转换为字符串，然后将其解析回DateTime值？如果它是数据库中的DateTime - 如果它不是它应该是 - 那么一个简单的演员将给你的价值，而不需要检查任何东西。



所以使用参数化查询，删除循环并检查行数（多个是某个地方的问题），确保您的数据库有teh ciorrect数据类型列，并用转换替换解析：

 dateTimePickerStartsFrom.Value =（DateTime）reader2 [ 从]开始; 

I have to get the date value from database and set that selected value to my datetimpicker while using dataReader.

[edit]Code block added - OriginalGriff[/edit]

What I have tried:

public void loadVoucher()
        {
            connection = new SqlConnection(DBHelper.ConnectionString());
            connection.Open();
            command = new SqlCommand();
            command.Connection = connection;
            command.CommandText = "select * from lease where linovice='" + txtLeaseVoucherNo.Text + "'";
            da = new SqlDataAdapter();
            da.SelectCommand = command;
            ds = new DataSet();
            da.Fill(ds);

            try
            {


                reader2 = command.ExecuteReader();
                {
                    while (reader2.Read())
                    {

                        txtName.Text  = (reader2["client_name"].ToString());
                        txtcFname.Text= (reader2["f_name"].ToString());
                       txtCNIC.Text   = (reader2["cnic"].ToString());
                       txtGName.Text  = (reader2["g_name"].ToString());
                       txtGFname.Text = (reader2["g_fname"].ToString());
                       txtGCnic.Text  = (reader2["g_cnic"].ToString());
                       txtGPhone.Text = (reader2["g_phone"].ToString());
                       txtGPhone2.Text= (reader2["g_phone2"].ToString());
                       txtGAdress.Text= (reader2["g_adress"].ToString());
                       txtGadress2.Text= (reader2["g_adress2"].ToString());
                       txtTotalBill.Text = (reader2["total_bill"].ToString());
                       txtAdvance.Text = (reader2["advance"].ToString());
                       txtPlan.Text = (reader2["lplan"].ToString());
                       txtLeaseAmount.Text = (reader2["lease_amu"].ToString());
                       txtInstalment.Text = (reader2["linstalment"].ToString());
                       txtSMName.Text = (reader2["sales_men"].ToString());
                       txtInspName.Text = (reader2["insp"].ToString());
                       comboBoxReceivedIn.Text = (reader2["GName"].ToString());
                       txtCurrentBal.Text = (reader2["balbefore"].ToString());
                       txtNewCurrentBal.Text = (reader2["balafter"].ToString());
                       DateTime datevalue;
                       if (DateTime.TryParse(reader2["startsfrom"].ToString(), out datevalue))
                       {
                          dateTimePickerStartsFrom.Value= datevalue;
                       }
                       else
                       {
                           // TODO - convertion failed... not a valid datetime
                           // Print it out and see what is wrong with it...
                       }
                       
                        txtChecque.Text = (reader2["checqueNo"].ToString());
                       txtPageNo.Text = (reader2["pageNo"].ToString());
                       

                    }
                   
                }
            }
            catch (Exception ex)
            {
                //  MessageBox.Show(ex.Message);


            }
            finally
            {
                connection.Close();
            }

        }

解决方案

First off, never do it like that! Do not concatenate strings to build a SQL command. It leaves you wide open to accidental or deliberate SQL Injection attack which can destroy your entire database. Use Parametrized queries instead.
Second, why are you using a loop to retrieve data? You always load it into the same place, so a look is silly - the last set of values will always be the only one displayed.
Third, why are you converting the database value to a string, then parsing it back to a DateTime value? If it's a DateTime in the database - and if it isn't it should be - then a simple cast will give your the value without needing to check anything.

So use a parameterised query, drop the loop and check the number of rows instead (more than one is a problem somewhere), make sure your DB has teh ciorrect datatype columns, and replace the parse with a cast:

dateTimePickerStartsFrom.Value = (DateTime) reader2["startsfrom"];

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