2

我正在尝试创建一个搜索，其中 SQL 查询取决于一个单选按钮和一个文本框。

SELECT * FROM [Sales] WHERE (text in radio button) = (text in textbox)

我该如何实施？

下面是我的完整代码。

Protected Sub btnSearch_Click(sender As Object, e As ImageClickEventArgs) Handles btnSearch.Click
    If radClient.Checked = True Then
        Dim connection As New OleDb.OleDbConnection
        Dim provider As String
        Dim source As String
        provider = "PROVIDER=Microsoft.Jet.OLEDB.4.0;"
        source = "Data Source=|DataDirectory|DeltaOneMDB.mdb"
        connection.ConnectionString = provider & source
        GridView1.Visible = False
        connection.Open()
        SqlDataSource3.SelectCommand = "SELECT * FROM Sales WHERE ClientID = '" & txtSearch.Text & "'"
        connection.Close()
    ElseIf radItem.Checked = True Then
        Dim connection As New OleDb.OleDbConnection
        Dim provider As String
        Dim source As String
        provider = "PROVIDER=Microsoft.Jet.OLEDB.4.0;"
        source = "Data Source=|DataDirectory|DeltaOneMDB.mdb"
        connection.ConnectionString = provider & source
        GridView1.Visible = False
        connection.Open()
        SqlDataSource3.SelectCommand = "SELECT * FROM Sales WHERE ItemID = '" & txtSearch.Text & "'"
        connection.Close()
    ElseIf radUser.Checked = True Then
        Dim connection As New OleDb.OleDbConnection
        Dim provider As String
        Dim source As String
        provider = "PROVIDER=Microsoft.Jet.OLEDB.4.0;"
        source = "Data Source=|DataDirectory|DeltaOneMDB.mdb"
        connection.ConnectionString = provider & source
        GridView1.Visible = False
        connection.Open()
        SqlDataSource3.SelectCommand = "SELECT * FROM Sales WHERE UserID = '" & txtSearch.Text & "'"
        connection.Close()
    ElseIf radUser.Checked = False And radClient.Checked = False And radItem.Checked = False Then
        ErrorLabel.Text = "Error: You have not chosen a search criteria."
    End If
End Sub

表格、文本框和单选按钮都在同一个表单上。我正在使用 Microsoft Visual Studio 2012 for Web，并尝试更改表单上 GridView 对象的数据源。但是，我不断收到错误消息：

ConnectionString 属性尚未初始化。

很抱歉没有早点给出我的代码。

谢谢！

4

3 回答 3

2

查看您的代码，我看到很多不必要的行。我想给你一个例子，说明我认为你可以做些什么来简化你的代码。首先，删除 SqlDataSource 不需要的代码（我假设您已经打开了与数据库的连接，但是这可以在单击条目时完成一次。其次，在每个开关中准备要执行的命令和参数（名称和值）传递给该命令最后更新您的 SqlDataSource 并重新绑定所有内容

Protected Sub btnSearch_Click(sender As Object, e As ImageClickEventArgs) Handles btnSearch.Click
    Dim sqlQuery As String
    Dim prm as String
    Dim prmValue as String

    prmValue = txtSearch.Text
    If radClient.Checked = True Then
        sqlQuery = "SELECT * FROM Sales WHERE ClientID = @clientID"
        prm = "@clientID"
    ElseIf radItem.Checked = True Then
        sqlQuery = "SELECT * FROM Sales WHERE ItemID = @itemID"
        prm = "@itemID"
    ElseIf radUser.Checked = True Then
        sqlQuery = "SELECT * FROM Sales WHERE UserID = @userID"
        prm = "@userID"
    ElseIf radUser.Checked = False And radClient.Checked = False And radItem.Checked = False Then
        ErrorLabel.Text = "Error: You have not chosen a search criteria."
        return
    End If
    SqlDataSource3.SelectCommand = sqlQuery
    SqlDataSource3.SelectParameters.Add(prm, prmValue)
    SqlDataSource3.DataBind()
End Sub
于 2013-03-20T14:57:41.327 回答
1

使用 SQLDatasource 时，您不必指定 Connections，它管理自己的连接。

你需要做的是：

  1. 根据单选按钮状态更新 Select 语句
  2. 调用数据源数据绑定函数SqlDataSource3.DataBind()

此外，更好的方法是使用允许空值的存储过程。更适合 SQL 注入（对您的数据库的威胁）

SELECT * FROM Sales WHERE (@ClientID IS NULL OR ClientID = @ClientID)
AND (@ItemID IS NULL OR ItemID = @ItemID )
AND (@UserIDIS NULL OR UserID= @UserID)
于 2013-03-20T14:48:30.087 回答
-1

互联网上到处都是可怕的解决方案。这可能是世界上最简单的。

PrintWriter out=response.getWriter();
        out.print("<html>");
        out.print("<body>");
        out.print("<form>");
        out.print("<textarea rows='5' columns='500' name='t1'></textarea>");
        //out.print("<input type='text' name='t2'>");
        //out.print("c<input type='checkbox' value='c' name='t1'>");
        //out.print("d<input type='checkbox' value='d' name='t1'>");
        out.print("<input type='submit' value='execute' name='b1'>");
    //  out.print("<input type='submit' value='show' name='b1'>");
        //out.print("<input type='submit' value='query' name='b1'>");

        String a,c;
        a=request.getParameter("t1");
        //b=request.getParameter("t2");
        c=request.getParameter("b1");
        if(c!=null)
            {
            try {
                Class.forName("com.mysql.jdbc.Driver");
                Connection con=DriverManager.getConnection("jdbc:mysql://localhost:3306/saransh","root","");
                Statement st=con.createStatement();

                if(a.startsWith("delete"))
                {
                    out.print("<br>");
                    out.print("delete query execution...");         

                    //st.executeUpdate("insert into student2(name,address) values('"+a+"',"+b+"')") ;
                    st.executeUpdate(a);
            }

                else if(a.startsWith("select"))
                {   out.print("<br>");
                    out.print("select query execution...");         
                    ResultSet rs=st.executeQuery(a);
                    ResultSetMetaData m1=rs.getMetaData();
                    out.print("<br>");
                    for(int i=1;i<=m1.getColumnCount();i++)
                    {String x1=m1.getColumnLabel(i);
                    out.print("   "+x1);}
                    out.print("<br>");//name of label               
                    while(rs.next())
                {   String s0=rs.getString("Stu_roll");
                    String s1=rs.getString("name");
                    String s2=rs.getString("address");

                out.print(s0+"   "+s1+"   "+s2);
                    out.print("<br>");  
                    }}

                else if(a.startsWith("insert"))
                {   out.print("<br>");
                out.print("insert query execution...");         

                    st.executeUpdate(a);
                }

                else if(a.startsWith("drop"))
                {   out.print("<br>");
                out.print("drop query execution...");           

                    st.executeUpdate(a);
                }
                } catch (Exception e) {

                out.print(e);
                // TODO: handle exception
            }
            }


        out.print("&lt;/form>");
        out.print("&lt;/body>");
        out.print("&lt;/html>");

删除注释行。唯一的问题是查询区分大小写。您可以弄清楚使用什么字符串操作使其“忽略大小写”。

于 2013-10-11T10:01:24.307 回答