我需要从多个文本框中更新SQL Server数据库。我有两个问题：
我的代码有什么问题（我的ID列可能有问题吗？（它是自动递增的）
我的WHERE是否足以在Employee表中找到完全匹配的内容以进行更新？
Employee包含7列：
Id (int), Name (nvarchar(max)), LastName(nvarcharmax), Age(int), Dep_nt(nvarchar(max)), Profession (nvarchar(max)), Salary (real).
我的代码：
private void button0_Click(object sender, RoutedEventArgs e)
{
using (SqlConnection connection = new SqlConnection(connectionString))
{
connection.Open();
var sql = String.Format("UPDATE Employee SET Name = @Name, LastName = @LastName, Age = @Age, Dep_nt = @Dep_nt, Profession = @Profession, Salary = @Salary WHERE ID = @ID", connection);
SqlCommand command = new SqlCommand(sql, connection);
command.Parameters.AddWithValue("@Name", NameF.Text);
command.Parameters.AddWithValue("@LastName", LastNameF.Text);
command.Parameters.AddWithValue("@Age", Convert.ToInt32(AgeF.Text));
command.Parameters.AddWithValue("@Dep_nt", DepartmentF.Text);
command.Parameters.AddWithValue("@Profession", ProfessionF.Text);
command.Parameters.AddWithValue("@Salary", Convert.ToDouble(SalaryF.Text));
//SqlParameter param = command.Parameters.Add("@ID", SqlDbType.Int, 0, "ID");
//param = command.Parameters.Add("@ID", SqlDbType.Int, 0, "ID");
//param.SourceVersion = DataRowVersion.Original;
adapter.UpdateCommand = command;
DataTable dt = new DataTable();
adapter.Fill(dt);
Ep.ItemsSource = dt.DefaultView;
connection.Close();
}
}
当前，我的代码绝对不执行任何操作。
我的应用程序的完整代码：
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Data;
using System.Data.SqlClient;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
namespace BigCompanyinc
{
/// <summary>
/// Логика взаимодействия для MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
{
Logic L = new Logic();
string connectionString = @"Data Source=(localdb)\MSSQLLocalDB;Initial Catalog=Hospital;Integrated Security=True;Pooling=False";
SqlDataAdapter adapter = new SqlDataAdapter();
public MainWindow()
{
InitializeComponent();
SqlConnection connection = new SqlConnection(connectionString);
SqlCommand command = new SqlCommand("SELECT DepartmentName FROM Department ", connection);
adapter.SelectCommand = command;
DataTable dataTable = new DataTable();
adapter.Fill(dataTable);
List<string> DepartmentNames = new List<string>();
for (int i = 0; i < dataTable.Rows.Count; i++)
{
String DepartmentName = Convert.ToString(dataTable.Rows[i]["DepartmentName"]);
DepartmentNames.Add(DepartmentName);
}
Department4.ItemsSource = DepartmentNames;
DepartmentF.ItemsSource = DepartmentNames;
DpListBox.ItemsSource = dataTable.DefaultView;
L.InitReadOnly(true, Name4, LastName4, Age4, Department4, Profession4, Salary4);
L.InitReadOnly(true, NameF, LastNameF, AgeF, DepartmentF, ProfessionF, SalaryF);
MessageBox.Show("Выберите департамент, чтобы начать работу.");
}
/// <summary>
/// Добавить новый департамент
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void Button2_Click(object sender, RoutedEventArgs e)
{
var sql = String.Format("INSERT INTO Department (DepartmentName) " + "VALUES (N'{0}')",
Name7.Text);
using (SqlConnection connection = new SqlConnection(connectionString))
{
connection.Open();
SqlCommand command = new SqlCommand(sql, connection);
command.ExecuteNonQuery();
command = new SqlCommand(@"UPDATE Deparment SET DepartmentName = @DepartmentName WHERE ID =@ID", connection);
command.Parameters.Add("@DepartmentName", SqlDbType.NVarChar, -1, "DepartmentName");
SqlParameter param = command.Parameters.Add("@ID", SqlDbType.Int, 0, "ID");
param.SourceVersion = DataRowVersion.Original;
adapter.UpdateCommand = command;
DataTable dataTable = new DataTable();
adapter.Fill(dataTable);
DpListBox.ItemsSource = dataTable.DefaultView;
connection.Close();
}
}
/// <summary>
/// Выбран новый элемент ListBox для коллекции департаментов
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void DpListBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
L.InitReadOnly(false, Name4, LastName4, Age4, Department4, Profession4, Salary4);
L.InitReadOnly(false, NameF, LastNameF, AgeF, DepartmentF, ProfessionF, SalaryF);
SqlConnection connection = new SqlConnection(connectionString);
connection.Open();
SqlDataAdapter adapter = new SqlDataAdapter();
DataRowView dataRowView = DpListBox.SelectedItem as DataRowView;
string value = "";
if (dataRowView != null)
{
value = dataRowView.Row["DepartmentName"] as string;
}
SqlCommand command = new SqlCommand($@"SELECT * FROM Employee WHERE Dep_nt='" + value + "'", connection);
adapter.SelectCommand = command;
DataTable dataTable1 = new DataTable();
adapter.Fill(dataTable1);
Ep.ItemsSource = dataTable1.DefaultView;
connection.Close();
}
private void Button1_Click(object sender, RoutedEventArgs e)
{
var sql = String.Format("INSERT INTO Employee (Name, LastName, Age, Dep_nt, Profession, Salary) " + "VALUES (N'{0}', '{1}', '{2}', '{3}', '{4}', '{5}')", Name4.Text, LastName4.Text, Age4.Text, Department4.Text, Profession4.Text, Salary4.Text);
using (SqlConnection connection = new SqlConnection(connectionString))
{
connection.Open();
SqlCommand command = new SqlCommand(sql, connection);
command.ExecuteNonQuery();
SqlConnection connection1 = new SqlConnection(connectionString);
SqlDataAdapter adapter = new SqlDataAdapter();
DataRowView dataRowView = DpListBox.SelectedItem as DataRowView;
string value = "";
if (dataRowView != null)
{
value = dataRowView.Row["DepartmentName"] as string;
}
SqlCommand command1 = new SqlCommand($@"SELECT * FROM Employee WHERE Dep_nt='" + value + "'", connection1);
adapter.SelectCommand = command1;
DataTable dataTable1 = new DataTable();
adapter.Fill(dataTable1);
Ep.ItemsSource = dataTable1.DefaultView;
connection.Close();
}
}
private void button0_Click(object sender, RoutedEventArgs e)
{
using (SqlConnection connection = new SqlConnection(connectionString))
{
connection.Open();
var sql = String.Format("UPDATE Employee SET Name = @Name, LastName = @LastName, Age = @Age, Dep_nt = @Dep_nt, Profession = @Profession, Salary = @Salary WHERE ID = @ID", connection);
SqlCommand command = new SqlCommand(sql, connection);
command.Parameters.AddWithValue("@Name", NameF.Text);
command.Parameters.AddWithValue("@LastName", LastNameF.Text);
command.Parameters.AddWithValue("@Age", Convert.ToInt32(AgeF.Text));
command.Parameters.AddWithValue("@Dep_nt", DepartmentF.Text);
command.Parameters.AddWithValue("@Profession", ProfessionF.Text);
command.Parameters.AddWithValue("@Salary", Convert.ToDouble(SalaryF.Text));
SqlParameter param = command.Parameters.Add("@ID", SqlDbType.Int, 0, "ID");
param = command.Parameters.Add("@ID", SqlDbType.Int, 0, "ID");
param.SourceVersion = DataRowVersion.Original;
adapter.UpdateCommand = command;
DataTable dt = new DataTable();
adapter.Fill(dt);
Ep.ItemsSource = dt.DefaultView;
connection.Close();
}
}
private void Ep_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
L.InitReadOnly(false, NameF, LastNameF, AgeF, DepartmentF, ProfessionF, SalaryF);
DataRowView dataRowView = Ep.SelectedItem as DataRowView;
if (dataRowView != null)
{
NameF.Text = dataRowView.Row["Name"] as string;
LastNameF.Text = dataRowView["LastName"] as string;
AgeF.Text = Convert.ToString(dataRowView["Age"]);
DepartmentF.Text = dataRowView["Dep_nt"] as string;
ProfessionF.Text = dataRowView["Profession"] as string;
SalaryF.Text = Convert.ToString(dataRowView["Salary"]);
}
else
{
NameF.Text = "";
LastNameF.Text = "";
AgeF.Text = "";
DepartmentF.Text = "";
ProfessionF.Text = "";
SalaryF.Text = "";
}
}
}
}
我使用WPF。 XAML代码：
<Window x:Name="Staff" x:Class="BigCompanyinc.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:local="clr-namespace:BigCompanyinc"
mc:Ignorable="d"
Title="Staff" Height="513.5" Width="991.833" ResizeMode="NoResize"
Icon="icon1.ico">
<Grid Height="504" VerticalAlignment="Top" Margin="10,0,-23,-19">
<Grid.RowDefinitions>
</Grid.RowDefinitions>
<TextBox x:Name="NameF" HorizontalAlignment="Left" Margin="164,418,0,0" VerticalAlignment="Top" Width="120" Height="22" IsReadOnly="False"/>
<TextBox x:Name="LastNameF" HorizontalAlignment="Left" Margin="294,418,0,0" VerticalAlignment="Top" Width="120" Height="22" IsReadOnly="False"/>
<TextBox x:Name="AgeF" HorizontalAlignment="Left" Margin="424,418,0,0" VerticalAlignment="Top" Width="120" Height="22" IsReadOnly="False"/>
<ComboBox x:Name="DepartmentF" HorizontalAlignment="Left" Margin="554,418,0,0" VerticalAlignment="Top" Width="120" Height="22" IsReadOnly="False"/>
<TextBox x:Name="ProfessionF" HorizontalAlignment="Left" Margin="684,418,0,0" VerticalAlignment="Top" Width="120" Height="22" IsReadOnly="False"/>
<TextBox x:Name="SalaryF" HorizontalAlignment="Left" Margin="814,418,0,0" VerticalAlignment="Top" Width="120" Height="22" IsReadOnly="False"/>
<Button x:Name="button0" HorizontalAlignment="Left" Margin="164,448,0,0" VerticalAlignment="Top" Width="120" Height="22" Background="LightBlue"
Content="Изменить данные" Click="button0_Click"/>
<TextBox x:Name="Name1" HorizontalAlignment="Left" Margin="164,386,0,0" VerticalAlignment="Top" Width="120" Height="22" Text="Имя" IsReadOnly="True"/>
<TextBox x:Name="LastName1" HorizontalAlignment="Left" Margin="294,386,0,0" VerticalAlignment="Top" Width="120" Height="22" Text="Фамилия" IsReadOnly="True"/>
<TextBox x:Name="Age1" HorizontalAlignment="Left" Margin="424,386,0,0" VerticalAlignment="Top" Width="120" Height="22" Text="Возраст" IsReadOnly="True"/>
<TextBox x:Name="Department1" HorizontalAlignment="Left" Margin="554,386,0,0" VerticalAlignment="Top" Width="120" Height="22" Text="Департамент" IsReadOnly="True"/>
<TextBox x:Name="Profession1" HorizontalAlignment="Left" Margin="684,386,0,0" VerticalAlignment="Top" Width="120" Height="22" Text="Профессия" IsReadOnly="True"/>
<TextBox x:Name="Salary1" HorizontalAlignment="Left" Margin="814,386,0,0" VerticalAlignment="Top" Width="120" Height="22" Text="Заработная плата" IsReadOnly="True"/>
<TextBox x:Name="Header1" HorizontalAlignment="Left" Margin="164,39,0,0" VerticalAlignment="Top" Width="250" Height="22" Text="Добавить сотрудника" IsReadOnly="True"/>
<TextBox x:Name="Name4" HorizontalAlignment="Left" Margin="164,99,0,0" VerticalAlignment="Top" Width="120" Height="22" IsReadOnly="False"/>
<TextBox x:Name="LastName4" HorizontalAlignment="Left" Margin="294,99,0,0" VerticalAlignment="Top" Width="120" Height="22" IsReadOnly="False"/>
<TextBox x:Name="Age4" HorizontalAlignment="Left" Margin="424,99,0,0" VerticalAlignment="Top" Width="120" Height="22" IsReadOnly="False"/>
<ComboBox x:Name="Department4" HorizontalAlignment="Left" Margin="554,99,0,0" VerticalAlignment="Top" Width="120" Height="22" IsReadOnly="False"/>
<TextBox x:Name="Profession4" HorizontalAlignment="Left" Margin="684,99,0,0" VerticalAlignment="Top" Width="120" Height="22" IsReadOnly="False"/>
<TextBox x:Name="Salary4" HorizontalAlignment="Left" Margin="814,99,0,0" VerticalAlignment="Top" Width="120" Height="22" IsReadOnly="False"/>
<TextBox x:Name="Name5" HorizontalAlignment="Left" Margin="164,69,0,0" VerticalAlignment="Top" Width="120" Height="22" Text="Имя" IsReadOnly="True"/>
<TextBox x:Name="LastName5" HorizontalAlignment="Left" Margin="294,69,0,0" VerticalAlignment="Top" Width="120" Height="22" Text="Фамилия" IsReadOnly="True"/>
<TextBox x:Name="Age5" HorizontalAlignment="Left" Margin="424,69,0,0" VerticalAlignment="Top" Width="120" Height="22" Text="Возраст" IsReadOnly="True"/>
<TextBox x:Name="Department5" HorizontalAlignment="Left" Margin="554,69,0,0" VerticalAlignment="Top" Width="120" Height="22" Text="Департамент" IsReadOnly="True"/>
<TextBox x:Name="Profession5" HorizontalAlignment="Left" Margin="684,69,0,0" VerticalAlignment="Top" Width="120" Height="22" Text="Профессия" IsReadOnly="True"/>
<TextBox x:Name="Salary5" HorizontalAlignment="Left" Margin="814,69,0,0" VerticalAlignment="Top" Width="120" Height="22" Text="Заработная плата" IsReadOnly="True"/>
<Button x:Name="button1" HorizontalAlignment="Left" Margin="164,129,0,0" VerticalAlignment="Top" Width="120" Height="22" Background="LightBlue"
Content="Добавить" Click="Button1_Click"/>
<TextBox x:Name="Header2" HorizontalAlignment="Left" Margin="10,39,0,0" VerticalAlignment="Top" Width="144" Height="22" Text="Добавить департамент" IsReadOnly="True"/>
<TextBox x:Name="Name6" HorizontalAlignment="Left" Margin="10,69,0,0" VerticalAlignment="Top" Width="144" Height="22" Text="Название" IsReadOnly="True"/>
<TextBox x:Name="Name7" HorizontalAlignment="Left" Margin="10,99,0,0" VerticalAlignment="Top" Width="144" Height="22" IsReadOnly="False"/>
<Button x:Name="button2" HorizontalAlignment="Left" Margin="10,129,0,0" VerticalAlignment="Top" Width="70" Height="22" Background="LightBlue"
Content="Добавить" Click="Button2_Click"/>
<TextBox x:Name="Department2" HorizontalAlignment="Left" Margin="10,12,0,0" VerticalAlignment="Top" Width="144" Height="22" Text="Департамент" IsReadOnly="True"/>
<ListBox SelectedItem="DepartmentName" x:Name="DpListBox" HorizontalAlignment="Left" Margin="10,165,0,138" Width="144" SelectionChanged="DpListBox_SelectionChanged">
<ListBox.ItemTemplate>
<DataTemplate>
<TextBlock Text="{Binding DepartmentName}"/>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
<ListView x:Name="Ep" HorizontalAlignment="Left" Height="201" Margin="164,165,0,0" VerticalAlignment="Top" Width="791" SelectionChanged="Ep_SelectionChanged">
<ListView.View>
<GridView>
<GridViewColumn Width="130" Header="Имя" DisplayMemberBinding="{Binding Name}"/>
<GridViewColumn Width="130" Header="Фамилия" DisplayMemberBinding="{Binding LastName}"/>
<GridViewColumn Width="130" Header="Возраст" DisplayMemberBinding="{Binding Age}"/>
<GridViewColumn Width="130" Header="Департамент" DisplayMemberBinding="{Binding Dep_nt}"/>
<GridViewColumn Width="130" Header="Профессия" DisplayMemberBinding="{Binding Profession}"/>
<GridViewColumn Width="130" Header="Заработная плата" DisplayMemberBinding="{Binding Salary}"/>
</GridView>
</ListView.View>
</ListView>
</Grid>
</Window>
答案 0 :(得分：0)
根据文档（@@IDENTITY (Transact-SQL) - Remarks）：
在完成INSERT，SELECT INTO或批量复制语句后， @@ IDENTITY包含由 声明。如果该语句不影响任何具有标识的表 列，@@ IDENTITY返回NULL。
您尚未在连接中执行INSERT，因此@@IDENTITY的值为NULL。
您需要将要更新的ID的值作为参数传递，就像您拥有的其他参数一样。将ID = @@IDENTITY更改为ID = @ID，然后添加另一个带有其值的参数（我无法告诉您该行的内容，因为我不知道您ID的值在哪里应用程序。）
答案 1 :(得分：0)
此部分的正确代码：
private void button0_Click(object sender, RoutedEventArgs e)
{
using (SqlConnection connection = new SqlConnection(connectionString))
{
DataRowView dataRowView = Ep.SelectedItem as DataRowView;
cmd = new SqlCommand("UPDATE Employee SET Name = @Name, LastName = @LastName, Age = @Age, Dep_nt = @Dep_nt, Profession = @Profession, Salary = @Salary WHERE ID = @ID", connection);
connection.Open();
cmd.Parameters.AddWithValue("@ID", dataRowView.Row["Id"] as Nullable<int>);
cmd.Parameters.AddWithValue("@Name", NameF.Text);
cmd.Parameters.AddWithValue("@LastName", LastNameF.Text);
cmd.Parameters.AddWithValue("@Age", Convert.ToInt32(AgeF.Text));
cmd.Parameters.AddWithValue("@Dep_nt", DepartmentF.Text);
cmd.Parameters.AddWithValue("@Profession", ProfessionF.Text);
cmd.Parameters.AddWithValue("@Salary", Convert.ToDouble(SalaryF.Text));
cmd.ExecuteNonQuery();
DataTable dt = new DataTable();
adapter.UpdateCommand = cmd;
adapter.Fill(dt);
Ep.ItemsSource = dt.DefaultView;
connection.Close();
}
}