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  • DropDownList的使用

      protected void Page_Load(object sender, EventArgs e)
        {
            if(!IsPostBack)
            {
                //初始化数据
                List<ClassInfo> list = new List<ClassInfo>();
                ClassInfo cls1 = new ClassInfo { ClassId=1,ClassName="S1101"};
                ClassInfo cls2 = new ClassInfo { ClassId = 2, ClassName = "S2101" };
                ClassInfo cls3 = new ClassInfo { ClassId = 3, ClassName = "S2102" };
                ClassInfo cls4 = new ClassInfo { ClassId = 4, ClassName = "S3001" };
    
                list.Add(cls1);
                list.Add(cls2);
                list.Add(cls3);
                list.Add(cls4);
    
    
                //绑定数据源
                this.ddlClass.DataSource = list;
                this.ddlClass.DataTextField = "ClassName";
                this.ddlClass.DataValueField = "ClassId";
    
                this.ddlClass.DataBind();//如果不写,会如何?
    
                //插入友好提示
                this.ddlClass.Items.Insert(0, "请选择班级");
    
            }
        }
        protected void ddlClass_SelectedIndexChanged(object sender, EventArgs e)
        {
            this.lblMessage.Text = "选择的班级信息 ClassId: "+this.ddlClass.SelectedValue.ToString()
                + "  ClassName: " + this.ddlClass.SelectedItem.ToString(); ;
        }

    页面层

     <form id="form1" runat="server">
        <div>
        
            班级:<asp:DropDownList ID="ddlClass" 
                runat="server" AutoPostBack="True" 
                onselectedindexchanged="ddlClass_SelectedIndexChanged">
            </asp:DropDownList>
            <br />
            <asp:Label ID="lblMessage" runat="server" Text=""></asp:Label>
        
        </div>
        </form>

    实体层

    public class ClassInfo
    {
        public ClassInfo()
        {
            
        }
        public int ClassId { get; set; }
        public string ClassName { get; set; }
    }

    后台代码

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  • 原文地址:https://www.cnblogs.com/914556495wxkj/p/3477793.html
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