如何从数据库中选择日期并将所选值设置为datetimepicker

本文介绍了如何从数据库中选择日期并将所选值设置为datetimepicker的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 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 { // 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"]; 这篇关于如何从数据库中选择日期并将所选值设置为datetimepicker的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！