Question

我正在尝试设置它，以便用户可以通过在文本框和组合框中输入详细信息来搜索datagridview中的特定记录。这是我的代码：

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Data.OleDb;

namespace RRAS
{
    public partial class formRRAS : Form
    {
        public OleDbConnection DataConnection = new OleDbConnection();


        public formRRAS()
        {
            InitializeComponent();

        }

        private void formRRAS_Load(object sender, EventArgs e)
        {
            // TODO: This line of code loads data into the 'database1DataSet.tblReject_test' table. You can move, or remove it, as needed.
            this.tblReject_testTableAdapter.Fill(this.database1DataSet.tblReject_test);

        }

        private void exitToolStripMenuItem_Click(object sender, EventArgs e)
        {
            this.Close();
        }

        private void btnSearch_Click(object sender, EventArgs e)
        {

            //This creates the String Publisher which grabs the information from the combo box on the form.
            //Select and Dataconnection are also defined here.
            string Select = "SELECT * FROM tblReject_test";
                string Department = txtDepartment.Text;
                string Start_Date = txtStart.Text;
                string End_Date = txtEnd.Text;
                string Anatomy = txtAnatomy.Text;
                string RFR = cmbRFR.Text;
                string Comment = txtComment.Text;

            //Select defines what should be loaded on to the dataset.
            if (Department != "")
            {
                Select = Select + " WHERE department_id =" + "'" + Department + "'";

                if (Anatomy != "")
                {
                    Select = Select + "AND body_part_examined =" + "'" + Anatomy + "'";

                    if (Start_Date != "")
                    {
                        Select = Select + " AND study_date =" + "'" + Start_Date + "'";

                        if (End_Date != "")
                        {
                            Select = Select + " AND study_date =" + "'" + End_Date + "'";

                            if (RFR != "")
                            {
                                Select = Select + " AND reject_category =" + "'" + RFR + "'";

                                if(Comment != "")
                                {
                                    Select = Select + " AND reject_comment =" + "'" + Comment + "'";
                                }
                            }
                        }
                    }
                }
            }
            else
            {
                Select = "SELECT * FROM tblReject_test";
            }
            //DataConnection connects to the database.
            string connectiontring = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=|DataDirectory|\\Database1.mdb";
            DataConnection = new OleDbConnection(connectiontring);

            //The DataAdapter is the code that ensures both the data in the Select and DataConnection strings match.
            OleDbDataAdapter rdDataAdapter = new OleDbDataAdapter(Select, DataConnection);

            try
            {
                //It then clears the datagridview and loads the data that has been selected from the DataAdapter.
                database1DataSet.tblReject_test.Clear();
                rdDataAdapter.Fill(this.database1DataSet.tblReject_test);
            }
            catch (OleDbException exc)
            {
                System.Windows.Forms.MessageBox.Show(exc.Message);
            }
        }

        private void btnLoadChart_Click(object sender, EventArgs e)
        {
            {
                string connectiontring = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=|DataDirectory|\\Database1.mdb";
                DataConnection = new OleDbConnection(connectiontring);

                try
                {
                    int count = database1DataSet.Tables["tblReject_test"].Rows.Count;

                    DataConnection.Open();
                    OleDbCommand command = new OleDbCommand();
                    command.Connection = DataConnection;
                    string query = "SELECT * FROM tblReject_test";
                    command.CommandText = query;

                    OleDbDataReader reader = command.ExecuteReader();
                    while (reader.Read())
                    {
                        charRejections.Series["RFR"].Points.AddXY(reader["reject_category"].ToString(), reader[count].ToString());
                    }

                    DataConnection.Close();
                }

                catch (Exception ex)
                {
                    MessageBox.Show("Error " + ex);
                }
            }
        }
    }
}

目前，该计划确实搜索了一些记录。它只会按if语句的顺序搜索记录。因此我不能将信息输入部门，然后再将RFR输入。如果我这样做，datagridview只会更新以显示我输入的部门的所有记录，它将忽略我输入RFR的信息。

Answer 1

我确信这不是最好的方法，但你可以考虑使用类似的东西：

    private void btnSearch_Click(object sender, EventArgs e)
            {

                //This creates the String Publisher which grabs the information from the combo box on the form.
                //Select and Dataconnection are also defined here.

                    //here you can check if the textbox.Text is empty and if it is use the % char to match anything
                    string Department = String.IsNullOrEmpty(txtDepartment.Text)? "%" : txtDepartment.Text;
                    string Start_Date = String.IsNullOrEmpty(txtStart.Text)? "%": txtStart.Text;
                    string End_Date = String.IsNullOrEmpty(txtEnd.Text)? "%" : txtEnd.Text;
                    string Anatomy = String.IsNullOrEmpty(txtAnatomy.Text)? "%":txtAnatomy.Text;
                    string RFR = String.IsNullOrEmpty(cmbRFR.Text)? "%" : cmbRFR.Text;
                    string Comment = String.IsNullOrEmpty(txtComment.Text)? "%":txtComment.Text;

            //the query could look like this:
                   string Select = "SELECT * FROM tblReject_test WHERE department_id LIKE '" +Department +"'" + "AND body_part_examined like'" + Anatomy +"'"+"AND study_date like'"+ Start_Date +"'";//and so on
           //rest of the code
    }

在select中，如果其中一个文本框中没有任何文字，我们会使用'%'通配符。

如果任何文本框不包含任何文本，则通过返回该列的任何值，将在查询中“忽略”该字段。如果所有文本框都为null，则查询将返回tblReject_test表中的所有值。

另外，请注意 SQL Injection 。

Answer 2

不要以你的级联方式放置你的ifs。尝试这样的事情：

string Select = "SELECT * FROM tblReject_test";
string Department = txtDepartment.Text;
string Start_Date = txtStart.Text;
string End_Date = txtEnd.Text;
string Anatomy = txtAnatomy.Text;
string RFR = cmbRFR.Text;
string Comment = txtComment.Text;
List<string> parameters = new List<string>();
bool first = true;

if (Department != "")
    parameters.Add("department_id =" + "'" + Department + "'");

if (Anatomy != "")
    parameters.Add("body_part_examined =" + "'" + Anatomy + "'");

if (Start_Date != "")
    parameters.Add("study_date =" + "'" + Start_Date + "'");

if (End_Date != "")
    parameters.Add("study_date =" + "'" + End_Date + "'");

if (RFR != "")
    parameters.Add("reject_category =" + "'" + RFR + "'");

if (Comment != "")
    parameters.Add("reject_comment =" + "'" + Comment + "'");

if (parameters.Count == 0)
    Select = "SELECT * FROM tblReject_test";

for (int i = 0; i < parameters.Count(); i++)
{ 
    if(i == 0)
        Select += " WHERE ";
    else
        Select += " AND ";
    Select += parameters[i];
}

在C＃中搜索数据集中的记录

2 个答案: