Question

我正在尝试使用droplistlist填充2个文本框我已经在default.aspx中定义了下拉列表，如下所示：

<asp:DropDownList ID="DropDownList1" runat="server" DataSourceID="SqlDataSource1" DataTextField="Player" DataValueField="ID" AppendDataBoundItems="true" AutoPostBack="true" OnSelectedIndexChanged="DropDownList1_SelectedIndexChanged">
<asp:ListItem Value="">Please Select</asp:ListItem></asp:DropDownList>`

<asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="<%$ ConnectionStrings:Phocas_WorkBenchConnectionString %>" SelectCommand="SELECT ID, [PlayerFirstName] + ' ' + [PlayerLastName] as 'Player' FROM [Players]"></asp:SqlDataSource>

我在default.aspx.cs中创建了C＃代码，如下所示：

protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
{

    SqlConnection sql = new SqlConnection(@"Data Source=DESKTOP-PMSK135\SQLEXPRESS;Initial Catalog=Phocas_WorkBench;Integrated Security=True");
    {
        SqlCommand getFirstName = new SqlCommand("Select PlayerFirstName from Players where ID = @PlayerID", sql);
        SqlCommand getLastName = new SqlCommand("Select PlayerLastName from Players where ID = @PlayerID", sql);
        getFirstName.Parameters.AddWithValue("@PlayerID", DropDownList1.SelectedValue);
        getLastName.Parameters.AddWithValue("@PlayerID", DropDownList1.SelectedValue);

        TextBox3.Text = getFirstName.CommandText;


        sql.Open(); //Opens Connection to the SQL Database using the definded Connection String. In this case the defined connection string is stored in "sql"
        string getResults = (string)getFirstName.ExecuteScalar();
        TextBox3.Text = getResults;
        getResults = (string)getLastName.ExecuteScalar();
        TextBox4.Text = getResults;
        sql.Close();

    }
}

我希望将2个SqlCommands的结果填充到textbox3和textbox4中，其中@PlayerID等于存储在下拉列表中的结果，其中DataValueField =＆＃34; ID＆＃34;因为ID是唯一标识符

谢谢

修改我的SQL查询出错，其中＆＃34; WHERE＆＃34;声明基于名称而非ID。这是一个错误，它总是被认为是ID。

我可以确认代码仍无法使用更正的SQL查询

Answer 1

对我来说，似乎你的default.aspx.cs中有一个错误的SQL语句。您应该根据ID选择播放器的名字和姓氏。您可以在1个声明中执行此操作：

SqlCommand getPlayerName = new SqlCommand("Select PlayerFirstName, PlayerLastName  from Players where ID = @PlayerID", sql);

当您在下拉列表中连接名字和姓氏以显示全名时，您无法在WHERE子句中使用此连接值

Answer 2

你的Sql查询应该是这个

SqlCommand getFirstName = new SqlCommand("Select PlayerFirstName from Players where Id= @PlayerID", sql);
    SqlCommand getLastName = new SqlCommand("Select PlayerLastName from Players where Id= @PlayerID", sql);

C＃使用下拉列表从SQL数据库中填充2个网页文本框

2 个答案: