DropDownList绑定数据库「建议收藏」

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//获取文本
this.DropDownList1.SelectedItem.Text;

本类内使用
protected void Page_Load(object sender, EventArgs e)
    {

        this.DropDownList1.Items.Clear();
        this.DropDownList1.DataSource = DbHelperSQL.Query(“select * from authors”).Tables[0];
        this.DropDownList1.DataTextField = “au_id”;
        this.DropDownList1.DataValueField = “au_lname”;
        this.DropDownList1.DataBind();               text value
        this.DropDownList1.Items.Insert(0,new ListItem(“”,””));//插入空项，此举必须放到数据绑定之后

    }
别忘了要判断isPostBack
//事件selectIndexChangeing
DropDownList的Items包括ListItem对象，ListItem有Value和Text两个属性，
取值取的是value不是text  this.DropDownList1.SelectValue;//value
this.DropDownList1.SelectValue://取当前文本框中所显示的键值
//公共方法
/// <summary>
    /// DropDownList绑定数据库
    /// </summary>
    /// <param name=”dropDownList”>本窗体上的dropDownList控件</param>
    /// <param name=”ds”>如：Db.Query(“select * from tbtype”)</param>
    /// <param name=”text”>dropDownList上显示的text文本值(数据库中的name)</param>
    /// <param name=”Value”>value值(对应数据库中的id)</param>
    /// <param name=”firstText”>dropdownlist首先显示的文本值(数据库中的name)</param>
    /// <param name=”firstValue”>firstText对应的键(数据库中的id)</param>
    public static void BindDropDownList(object dropDownList, DataSet ds, string text, string Value, string firstText, string firstValue)
    {

        if (dropDownList == null || ds == null)
        {

            return;
        }

        if (dropDownList is System.Web.UI.WebControls.DropDownList)
        {

            ((System.Web.UI.WebControls.DropDownList)dropDownList).Items.Clear();

            ((System.Web.UI.WebControls.DropDownList)dropDownList).DataTextField = text;
            ((System.Web.UI.WebControls.DropDownList)dropDownList).DataValueField = Value;
            ((System.Web.UI.WebControls.DropDownList)dropDownList).DataSource = ds.Tables[0];
            ((System.Web.UI.WebControls.DropDownList)dropDownList).DataBind();
            ((System.Web.UI.WebControls.DropDownList)dropDownList).Items.Insert(0, new System.Web.UI.WebControls.ListItem(firstText, firstValue));//dropdownlist首次显示的text,value
            //if (((DropDownList)dropDownList).Items.Count > 0)
            //{

            //    ((DropDownList)dropDownList).SelectedIndex = 0;//首先显示第一项
            //}
        }

    }
————————-
上面方法重载，参数中没有“全部”，“全部”，即首次显示的不是”全部“
/// <summary>
    /// DropDownList绑定数据库
    /// </summary>
    /// <param name=”dropDownList”>本窗体上的dropDownList控件</param>
    /// <param name=”ds”>如：Db.Query(“select * from tbtype”)</param>
    /// <param name=”text”>dropDownList上显示的text文本值(数据库中的name)</param>
    /// <param name=”Value”>value值(对应数据库中的id)</param>
    /// <param name=”firstText”>dropdownlist首先显示的文本值(数据库中的name)</param>
    /// <param name=”firstValue”>firstText对应的键(数据库中的id)</param>
    public static void BindDropDownList(object dropDownList, DataSet ds, string text, string Value)
    {

        if (dropDownList == null || ds == null)
        {

            return;
        }

        if (dropDownList is System.Web.UI.WebControls.DropDownList)
        {

            ((System.Web.UI.WebControls.DropDownList)dropDownList).Items.Clear();

            ((System.Web.UI.WebControls.DropDownList)dropDownList).DataTextField = text;
            ((System.Web.UI.WebControls.DropDownList)dropDownList).DataValueField = Value;
            ((System.Web.UI.WebControls.DropDownList)dropDownList).DataSource = ds.Tables[0];
            ((System.Web.UI.WebControls.DropDownList)dropDownList).DataBind();
            //((System.Web.UI.WebControls.DropDownList)dropDownList).Items.Insert//(0, new System.Web.UI.WebControls.ListItem(firstText, firstValue));//dropdownlist首次显示的text,value
            //if (((DropDownList)DropDownList).Items.Count > 0)
            //{

            //    ((DropDownList)DropDownList).SelectedIndex = 0;
            //}
        }

    }
//调用时要判断isPostBack
—————————————————————
protected void Page_Load(object sender, EventArgs e)
    {

       
        if (!IsPostBack)
        {

          
            PublicClass.BindDropDownList(this.DropDownList1, Db.Query(“select * from BookType”), “BookTypeName”, “BookTypeId”, “全部”, “全部”);
        }
    }
——————————————————————–
//添加项
DataTable dt = Spbase.GreatDs(“Select * from Spclass”).Tables[0];
        for (int i = 0; i < dt.Rows.Count; i++)
        {

            ListItem Dr = new ListItem(dt.Rows[i][“name”].ToString(), dt.Rows[i][0].ToString());
            DropDownList1.Items.Add(Dr);

        }