Question

我正在尝试检查数据库中是否存在特定值，但是我想要的是

我想从JavaScript中调用C＃函数
就像现在我的代码在JavaScript点击按钮后响应但是页面也刷新我不希望页面刷新发生

使用javascript

按钮调用C＃函数的更好方法

protected void Check_exam_id(object sender, EventArgs e)
{         
    string DDSelected_Class = DD_class.SelectedValue;// store it in some variable;
    string DD__Method = DD_Method.SelectedValue;// store it in some variable;

    if (DD__Method == "THEORY")

        {
    using (MySqlConnection myConnection = new MySqlConnection(constr))
    {
        string oString = "Select * from score_master WHERE Class=@DDSelected_Class ";
        MySqlCommand oCmd = new MySqlCommand(oString, myConnection);
        oCmd.Parameters.AddWithValue("@DDSelected_Class", DDSelected_Class);

        myConnection.Open();
        using (MySqlDataReader oReader = oCmd.ExecuteReader())
        {

            if (oReader == null || !oReader.HasRows)
            {
                ScriptManager.RegisterStartupScript(this, typeof(Page), "alert", "alert('No Student Found')", true);


            }
            else
            {
                ScriptManager.RegisterStartupScript(this, typeof(Page), "alert2", "alert('Exist')", true);

                myConnection.Close();
            }
        }

    }


    }

}

asp按钮

 <asp:Button runat="server" id="Check_examid"  AutoPostback = "false" onclick='Check_exam_id'   style="  display:none;   float: right;    width: 22%;    height: 41px;    text-align: center;    background: #EAEAEA;    border: none;    border-color: #EAEAEA;    margin-top: 2%;" Text="Submit"></asp:Button>

Javascript

    document.getElementById("BodyHolder_Check_examid").click()

Answer 1

将其作为web方法，并使用ajax从jquery调用该方法。请找到以下链接，它包含使用jquery ajax在asp.net中调用webmethods的示例。 http://www.aspsnippets.com/Articles/Calling-ASPNet-WebMethod-using-jQuery-AJAX.aspx

希望这有帮助！

Answer 2

正如评论中所提到的，您可以使用 jquery ajax 轻松完成。为此，您必须定义类似这样的WebMethod： -

请加入using System.Web.Services;。

[WebMethod]
public static bool Check_exam_id(string className, string MethodName)
{
    bool examIdExist = false;
    if (DD__Method == "THEORY")
    {
        \\Your logic here
    }
    \\Based on DB operation return value
    examIdExist 
}

最后从你的客户端这样打电话： -

$("#Check_examid").click(function (e) {
    e.preventDefault(); //To avoid postback
    //Get these values from dropdwon
    var className = $("#DD_class").val();
    var methodName = $("#DD_Method").val();
    var data = { "className": className , "MethodName": methodName };  
    $.ajax({
        type: "POST",
        dataType: "json",
        contentType: "application/json; charset=utf-8",
        url: "Default.aspx/Check_exam_id",
        data: JSON.stringify(data),
        success: function (response) {
            if(response.d)  //If method returned true.
               alert('Exist');
            else
               alert('No Student Found')
        },
        error: function (msg) { alert(msg.d); }
    });
});

另外，包括jquery基本库文件。

Answer 3

使用Jquery ajax方法或使用UpdatePanels

将方法Check_exam_id创建为公共静态并将其装饰为[WebMethod] 当你调用任何其他函数时，在按钮的click事件上调用javascript函数。

    function DoWork(){
     $.ajax({
          url: 'YourPage.aspx/Check_exam_id',
          data: {}, //blank since you are sending nothing
          dataType:'JSON',
          type: 'POST',
          contentType:'application/json;charset=utf-8',
          success:function(){
          alert('Success');
          //Do whatever you want with the HTML
          },
         error:function()
         {
          alert('Error');
            }
         });
        }

Answer 4

$("#Check_examid").click(function (e) {
    e.preventDefault(); //To avoid postback
    //Get these values from dropdwon
    var className = $("#DD_class").val();
    var methodName = $("#DD_Method").val();
    var data = { "className": className , "MethodName": methodName };  
    $.ajax({
        type: "POST",
        dataType: "json",
        contentType: "application/json; charset=utf-8",
        url: "Default.aspx/Check_exam_id",
        data: JSON.stringify(data),
        success: function (response) {
            if(response!=null)  //If method returned true.
               alert('Exist');
$("DivId").html(response.d)
            else
               alert('No Student Found')
        },
        error: function (msg) { alert(msg.d); }
    });
});

调用asp.net函数，直接从java脚本单击out按钮，不用页面刷新

4 个答案: