ASP.NET listBbox控件用法

ListBox基本功能使用方法  

2011-06-09 13:23:16|  分类: .NET/C# |  标签:listbox基本功能使用方法   |举报 |字号 订阅

 
 
  1. ListBox基本功能使用方法

 

ListBox基本功能首先是列表项的添加,客户端实现代码添加在listbox实例化代码中间,例如:

<asp:ListItem Value="value" Selected=True>Text</asp:ListItem>

若在服务器端实现,为避免每次加载时执行添加列表项,上述代码包含在下面代码中:

if(!IsPostBack)

{

}

WebForm页面上须添加2个listbox(listbox1和lixtbox2)和2个命令按钮,listbox1不为空。列表项从listbox1添加到listbox2须在Button1单击事件中调用Add方法:

ListBox2.Items.Add(ListBox1.SelectedValue);

若要从listbox2中删除列表项的话须在Button2单击事件中调用Remove方法:

ListBox2.Items.Remove(ListBox2.SelectedValue);

列表项从listbox1添加到listbox2后,列表项从listbox1中删除:

int i=0;

while(i<ListBox1.Items.Count)

{

if(ListBox1.Items[i].Selected==true)

{

ListBox2.Items.Add(ListBox1.Items[i]);

ListBox1.Items.Remove(ListBox1.Items[i]);

}

else

i+=1;

}

这样只能实现单项添加,想要实现多项添加,首先设置ListBox1的SelectionMode属性值Multiple,ListBox1允许多项选中。

在Button1单击事件中添加

foreach(ListItem MyItem in ListBox1.Items)

if(MyItem.Selected==true)

ListBox2.Items.Add(MyItem);

想要一次清空ListBox2中所有选项可在Button2单击事件中调用clear方法,

ListBox2.Items.Clear();

若列表项已经添加,不允许二次添加,Button1单击事件中的代码包含在:

if(ListBox2.Items.FindByValue(ListBox1.SelectedValue)==null)

{

}

ListBox与数据库绑定就是指定他的DataSource和DataTextField属性,

ListBox2.DataSource=数据源;

ListBox2.DataTextField="字段名";

ListBox2.DataBind();

 


 

<script type="text/javascript">
        function SelectAll()
        {
            var lst1=window.document.getElementById("<%=lb_Sourse.ClientID %>");
            var length = lst1.options.length;
             var string = window.document.getElementById("<%=hf_NewName.ClientID %>")
            for(var i=0;i<length;i++)
            {
                var v = lst1.options[i].value;
                var t = lst1.options[i].text;             
                var lst2=window.document.getElementById("<%=lb_NewName.ClientID %>");
                lst2.options[i] = new Option(t,v,true,true);
                string.value+=v;
            }
        }
        
        function DelAll()
        {
            var lst2=window.document.getElementById("<%=lb_NewName.ClientID %>");
            var length = lst2.options.length;
            for(var i=length;i>0;i--)
            {
                lst2.options[i-1].parentNode.removeChild(lst2.options[i-1]);
            }
        }
        
        function SelectOne()
        {
          var string = window.document.getElementById("<%=hf_NewName.ClientID %>")
            var lst1=window.document.getElementById("<%=lb_Sourse.ClientID %>");
            var lst2=window.document.getElementById("<%=lb_NewName.ClientID %>");
            var lstindex=lst1.selectedIndex;
            var length = lst2.options.length;
            var isExists = false;
            if(lstindex<0)
                return;
            else if(length != null)
            {
                for(var i=0;i < length; i++)
                {
                     if(lst2.options[i].text == lst1[lstindex].text&&lst2.options[i].value == lst1[lstindex].value)
                     {
                        isExists = true;
                     }
                }
            }
            else
            {
                return;
            }
            if (isExists == false)
            {
                var v = lst1.options[lstindex].value;
                var t = lst1.options[lstindex].text;
                lst2.options[lst2.options.length] = new Option(t,v,true,true);
                string.value+=v;
            }
            else
            {
                alert("所选条目已经存在");
                return false;
            }
        }
        
        function DelOne()
        {
            var lst2=window.document.getElementById("<%=lb_NewName.ClientID %>");
            var lstindex=lst2.selectedIndex;
            if(lstindex>=0)
            {
                var v = lst2.options[lstindex].value+";";
                lst2.options[lstindex].parentNode.removeChild(lst2.options[lstindex]);
            }
        }
</script>

需要解释的是由于JS脚本是在客户端执行的,因此服务器端控件是无法调用JS的,由于ID无法被找到,但用<%=lb_NewName.ClientID %>的方法就巧妙的解决得该问题,是asp控件拥有客户端id,这样就可以调用了。

希望对大家有所帮助!

 


 

ASP.NET中添加控件ListBox , 属性设为 Multiple , 则可进行多选.
就以两个listbox之间多选添加项目为例.
两个控件为listboxleft , listboxright 定义了一个动态数组用于中间存储 arrRight .具体代码如下:

//读取右边选中项目
   ArrayList arrRight = new ArrayList();
   foreach(ListItem item in this.ListBoxRight.Items) //按类型listitem读取listbox中选定项
   {
    if(item.Selected) //判断是否选中
    {
     arrRight.Add(item);
    }
   }  

   //右边移除选定项目 左边添加
   foreach(ListItem item in arrRight)
   {
    this.ListBoxLeft.Items.Add(item);
    this.ListBoxRight.Items.Remove(item);
   }
不能将item的添加删除直接写在if(item.Selected){}内,因为项目remove后会出现错误


 

添加两个listbox (ListBoxAll , ListBoxUser)    两个按钮( ButtonListDel >> , ButtonListAdd <<)

按钮的代码为:

private void ButtonListDel_Click(object sender, System.EventArgs e)
  {
   //listbox >> 删除listboxuser选中项目 将其添加入listboxall
   if(this.ListBoxUser.SelectedIndex != -1)
   {
    this.ListBoxAll.Items.Add(this.ListBoxUser.SelectedItem.Value);
    this.ListBoxUser.Items.Remove(this.ListBoxUser.SelectedItem.Value); 
   }
  }

  private void ButtonListAdd_Click(object sender, System.EventArgs e)
  {
   //listbox << 
   if(this.ListBoxAll.SelectedIndex != -1)
   {
    this.ListBoxUser.Items.Add(this.ListBoxAll.SelectedItem.Value);
    this.ListBoxAll.Items.Remove(this.ListBoxAll.SelectedItem.Value);
   }
  }

1 为了确保添加不会重复 填充listbox时使两边无重复项目.

完成listbox里项目的添加、删除的关键代码:

1.通过AddRange方法添加项目:this.lbyx.Items.AddRange(new object[] {"北京","上海","天津","成都","广州","深圳","武汉"});

2.添加items:this.lbbx.Items.Add(this.lbyx.Text);

3.清空列表内的所有items:this.lbbx.Items.Clear();

4.当前所选项的编号获取:this.lbbx.SelectedIndex

5.删除某项:this.lbbx.Items.RemoveAt(this.lbbx.SelectedIndex);

 


 

在从一个ListBox选择内容copy到另外一个ListBox时候用下面的方法:

if (ListBox2.Items.IndexOf(ListBox1.SelectedItem) == -1)
        {
            ListBox2.Items.Add(new ListItem(ListBox1.SelectedValue));
            //ListBox2.Items.Add(ListBox1.SelectedItem);  <--用这个会记录状态,ListBox2不支持Multiple就出错了
}

===================================================================

<asp:listbox width="100px" runat=server>
                    <asp:listitem>Roman</asp:listitem>
                    <asp:listitem>Arial Black</asp:listitem>
                    <asp:listitem>Garamond</asp:listitem>
                    <asp:listitem>Somona</asp:listitem>
                    <asp:listitem>Symbol</asp:listitem>
                 </asp:listbox>

 void RemoveAllBtn_Click(Object Src, EventArgs E) {

            while (InstalledFonts.Items.Count != 0) {

               AvailableFonts.Items.Add(new ListItem(InstalledFonts.Items[0].Value));
               InstalledFonts.Items.Remove(InstalledFonts.Items[0].Value);
            }
        }
当数据源改为

<asp:listbox width="100px" runat=server>
                    <asp:listitem value="1">Roman</asp:listitem>
                    <asp:listitem value="bbb">Arial Black</asp:listitem>
                    <asp:listitem value="333">Garamond</asp:listitem>
                    <asp:listitem value="4">Somona</asp:listitem>
                    <asp:listitem value="5">Symbol</asp:listitem>
                 </asp:listbox>

listbox.items.count会一直为总数,不会顺while循环的变化,可以修改为如果方法:

  #region button

  private void btnRemoveAll_Click(object sender, System.EventArgs e)
  {
   while (lstSelDpt.Items.Count != 0) 
   {
    lstAllDpt.Items.Add(lstSelDpt.Items[lstSelDpt.Items.Count-1]);
    lstSelDpt.Items.RemoveAt(lstSelDpt.Items.Count-1);
   }

  }

  private void btnRemove_Click(object sender, System.EventArgs e)
  {
   while(lstSelDpt.SelectedIndex != -1) 
   {
    lstAllDpt.Items.Add(lstSelDpt.Items[lstSelDpt.SelectedIndex]);
    lstSelDpt.Items.Remove(lstSelDpt.Items[lstSelDpt.SelectedIndex]);
   }
  }

  private void btnAdd_Click(object sender, System.EventArgs e)
  {   
   while (lstAllDpt.SelectedIndex != -1) 
   {
    lstSelDpt.Items.Add(lstAllDpt.Items[lstAllDpt.SelectedIndex]);
    lstAllDpt.Items.Remove(lstAllDpt.Items[lstAllDpt.SelectedIndex]);
   }
  }

  private void btnAddAll_Click(object sender, System.EventArgs e)
  {
   while (lstAllDpt.Items.Count != 0) 
   {
    lstSelDpt.Items.Add(lstAllDpt.Items[lstAllDpt.Items.Count-1]);
    lstAllDpt.Items.Remove(lstAllDpt.Items[lstAllDpt.Items.Count-1]);
   }

  }

  #endregion

 


 

用dotnet做一个项目的过程中,遇到了一个ListBox的问题:通过在一个ListBox中双击,把选中的项添加到另一个ListBox中,但ListBox控件本身并没有该事件,那么如何实现呢?我就想到了客户端脚本javascrit,通过查阅相关资料,终于把这个问题解决了,现在写出来与大家分享,希望能对大家有所帮助。
        这里有三个问题:
        第一:双击所要执行的javascript代码是什么?
                    注意:javascript代码的语法要正确,即每一行都要以“;”结尾;
                    function change()
                        {
                             var addOption=document.createElement("option");
                             var index1;
                             if(document.Form1.ListBox1.length==0)return(false);
                              index1=document.Form1.ListBox1.selectedIndex; 
                             if(index1<0)return(false);
                              addOption.text=document.Form1.ListBox1.options(index1).text;
                              addOption.value=document.Form1.ListBox1.value;
                             document.Form1.ListBox2.add(addOption);
                             document.Form1.ListBox1.remove (index1);
                         }
        第二:如何将 javascript 代码转换为C#代码?
                    public static void ListBox_DblClick(Page page,System.Web.UI.WebControls.WebControl webcontrol,string                                 SourceControlName,string TargetControlName)
                     {
                           SourceControlName = "document.Form1." +  SourceControlName;
                           TargetControlName = "document.Form1." +  TargetControlName;
                           string js = "<script language=javascript> function change(SourceControlName,TargetControlName)";
                           js += "{";
                           js +=     "var addOption=document.createElement(‘option‘); \n";
                           js += "  var index1; \n";
                           js += "if(SourceControlName.length==0)return(false);\n";
                           js += "  index1=SourceControlName.selectedIndex; \n ";
                           js += "  if(index1<0)return(false);\n";
                           js += " addOption.text=SourceControlName.options(index1).text; \n";
                           js += "addOption.value=SourceControlName.value; \n";
                           js += "TargetControlName.add(addOption); \n";
                           js += "SourceControlName.remove (index1) \n";

                           js +="}";
                           js += "</script>";
                            //注册该 javascript ;
                           page.RegisterStartupScript("",js);
                            //为控件添加双击事件;
                           webcontrol.Attributes.Add("onDblClick","change(" + SourceControlName + "," + TargetControlName +                                 ");");
                      }
                    在该方法中,SourceControlName是要绑定双击事件的控件,TargetControlName是接收双击事件选定项的控件。    
                    这里有一个问题,如何让对象作为参数传给javascript的change函数,我这里采用的是用  SourceControlName  ,TargetControlName 来传递两个ListBox的Name, 然后与“document.Form1.“组合成一个串来传递给javascript的change函数,即 
                            SourceControlName = "document.Form1." +  SourceControlName;
                           TargetControlName = "document.Form1." +  TargetControlName;

        第三:如何为控件添加双击事件?
                    用ControlName.Attributes.Add(“属性名称”,“函数名称或代码”);

ASP.NET listBbox控件用法,古老的榕树,5-wow.com

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