webapi+EF(增删改查)

第一步，Model建立Ado.net实体模型。

第二部，Controller建立增删查改方法

        public static HttpResponseMessage toJson(Object obj)
        {
            String str;
            if (obj is String || obj is Char)
            {
                str = obj.ToString();
            }
            else
            {
                JavaScriptSerializer serializer = new JavaScriptSerializer();
                str = serializer.Serialize(obj);
            }
            HttpResponseMessage result = new HttpResponseMessage { Content = new StringContent(str, Encoding.GetEncoding("UTF-8"),   "application/json")  };
            return result;
        }

        public HttpResponseMessage get()
        {

            var jg = db.user.ToList();
            return toJson(jg);

        }

      protected override void Dispose(bool disposing)
        {
            db.Dispose();
            base.Dispose(disposing);
        }

连接数据库：vs界面左侧服务器资源管理器中连接数据库，在web.config中修改或添加

  <connectionStrings>
    <add name="DefaultConnection" providerName="System.Data.SqlClient" connectionString="Data Source=(LocalDb)v11.0;Initial Catalog=aspnet-webapitest1-20170420100509;Integrated Security=SSPI;AttachDBFilename=|DataDirectory|aspnet-webapitest1-20170420100509.mdf" />
    <add name="testDBEntities" connectionString="metadata=res://*/Models.Model1.csdl|res://*/Models.Model1.ssdl|res://*/Models.Model1.msl;provider=System.Data.SqlClient;provider connection string=&quot;data source=.;initial catalog=testDB;persist security info=True;user id=sa;password=123456; MultipleActiveResultSets=True;App=EntityFramework&quot;" providerName="System.Data.EntityClient" />
  </connectionStrings>

第三部：view视图页面 Index.cshtml

@{
    Layout = null;
}
<script src="~/Scripts/jquery-1.7.1.min.js"></script>
<table id="customerTable" border="0" cellpadding="3">
    <tr>
        <th>UserID</th>
        <th>login</th>
        <th>pwd</th>
        <th>Actions</th>
    </tr>
    <tr>
        <td>
            <input type="text" id="txtCustomerId" size="5" />
        </td>
        <td>
            <input type="text" id="txtCompanyName" />
        </td>
        <td>
            <input type="text" id="txtContactName" />
        </td>
        <td>
            <input type="button" name="btnInsert" value="Insert" />
        </td>
    </tr>
</table>
<script type="text/javascript">
    $(function () {
        $.getJSON("api/user", LoadCustomers);
    });
    function LoadCustomers(data) {
        $("#customerTable").find("tr:gt(1)").remove();
        $.each(data, function (key, val) {
            var tableRow = '<tr>' + '<td>' + val.userId + '</td>' +
            '<td><input type="text" value="' + val.login + '" /></td>' +
            '<td><input type="text" value="' + val.pwd + '" /></td>' +
            '<td><input type="button" name="btnUpdate" value="修改" />' +
            '<input type="button" name="btnDelete" value="删除" /></td>' +
            '</tr>';
            $('#customerTable').append(tableRow);
        });
        $("input[name='btnInsert']").click(OnInsert);
        $("input[name='btnUpdate']").click(OnUpdate);
        $("input[name='btnDelete']").click(OnDelete);
    }
    function OnInsert() {
        var userId = $("#txtCustomerId").val();
        var login = $("#txtCompanyName").val();
        var pwd = $("#txtContactName").val();
        var data = '{"userId":"' + userId + '","login":"' + login + '","pwd":"' + pwd + '"}}';
        $.ajax({
            type: 'POST',
            url: '/api/user',
            data: data,
            contentType: "application/json; charset=utf-8",
            dataType: 'json',
            success: function (result) {
                $("#txtCustomerId").val('');
                $("#txtCompanyName").val('');
                $("#txtContactName").val('');
                $("#txtCountry").val('');
                $.getJSON("api/user", LoadCustomers);
                alert('Customer Added !');
            }
        }).fail(
    function (xhr, textStatus, err) {
        alert('添加失败，原因如下: ' + err);
    });

    }
    function OnUpdate() {

        var userId = $(this).parent().parent().children().get(0).innerHTML;;

        var login = $($(this).parent().parent().children().get(1)).find("input").val();

        var pwd = $($(this).parent().parent().children().get(2)).find("input").val();;


        var data = '{"userId":"' + userId + '","login":"' + login + '","pwd":"' + pwd + '"}}';

        $.ajax({
            type: 'PUT',
            url: '/api/user/' + userId,
            data: data,
            contentType: "application/json; charset=utf-8",
            dataType: 'json',
            success: function (results) {
                $.getJSON("api/user", LoadCustomers);
                alert('Customer Updated !');
            }
        }).fail(function (xhr, textStatus, err) {
            alert('Failed update! The reason is : ' + err);
        });
    }
 
    function OnDelete() {
        var userId = $(this).parent().parent().children().get(0).innerHTML;
        $.ajax({
            type: 'DELETE',
            url: '/api/user/' + userId,
            contentType: "application/json; charset=utf-8",
            dataType: 'json',
            success: function (results) {
                $.getJSON("api/user", LoadCustomers);
                alert('Customer Deleted!');
            }
        }).fail(function (xhr, textStatus, err) {
            alert("Delete error ! The reason is :" + err);
        });

    }
</script>