如何使用ajax使用实体框架在ASP.NET mvc5中按下拉列表填充表单字段 [英] How to populate a form field by dropdownlist in ASP.NET mvc5 with entity framework using ajax
问题描述
我在选择'TeacherId'DropDownList项后尝试自动填充CreditTobeTakenTextBox。我在数据库中有Teacher Table，其中TeacherId是主键，并尝试检索特定教师的CreditToBeTaken。但它不起作用。我在codeproject中看到了类似的示例，但它们并不适用于我。我认为我的ajax调用存在问题。请有人帮助我。
我尝试过的事情：
行动：
public JsonResult CreditToBeTaken（int id）
{
db .Configuration.ProxyCreationEnabled = false;
string credit =从Teacher选择CreditToBeTaken，其中TeacherId ='+ id +';
var creditsToBeTaken = db.Teachers.SqlQuery （信用）;
返回Json（creditsToBeTaken）;
}
查看：
@ Html.LabelFor（model => model.TeacherId，TeacherId，htmlAttributes：new {@class =control-label col -md-2}）
@ Html.DropDownList（TeacherId，新的SelectList（string.Empty） ，价值，文字），请选择一位教师，htmlAttributes：new {@class =form-control}）
@ Html.ValidationM essageFor（model => model.TeacherId，，new {@class =text-danger}）
@ Html.LabelFor（model => model.CreditToBeTaken，htmlAttributes：新{@class =control-label col-md-2}）
@ Html.EditorFor（ model => model.CreditToBeTaken，new {@id =creditTobeTakenTextBox，@ class =form-control}
@ Html.ValidationMessageFor（model => model.CreditToBeTaken，，新{@class =text-danger}）
脚本文件：
< script>
$ （文件）.ready（function（）{
$（＃teacherId）。change（function（）{
$ .ajax（{
url：'@ Url.Action（CreditTo BeTaken）'，
类型：'POST'，
dataType：'json'，
数据：{teacherID：$（＃ TeacherId）。val（）}，
contentType：'application / json; charset = utf-8'，
成功：函数（数据）{
if（data.success）{
//填充信用要采取
$（＃CreditToBeTakenTextBox）。val（data.creditsToBeTaken）;
}
else {
//在警告或div中显示消息
alert（'此教师ID无效。请重试！'）;
}
}
}）;
}）;
}）;
< / script>
（文件）.ready（function（ ）{
（＃teacherId）。change（function（）{
.ajax（{
url：'@ Url.Action （CreditToBeTaken）'，
类型：'POST'，
dataType：'json'，
数据：{teacherID：
I am trying to populate CreditTobeTakenTextBox automatically after selecting a 'TeacherId' DropDownList item. I have Teacher Table in database where TeacherId is a primary key, and trying to retrieve CreditToBeTaken of a particular teacher. But it's not working. I have seen similar type of example in codeproject but they are not working for me. I think there is a problem in my ajax call. Please someone help me.
What I have tried:
Action:
public JsonResult CreditToBeTaken(int id)
{
db.Configuration.ProxyCreationEnabled = false;
string credit = "select CreditToBeTaken from Teacher where TeacherId='"+id+"'";
var creditsToBeTaken = db.Teachers.SqlQuery(credit);
return Json(creditsToBeTaken);
}
View:
@Html.LabelFor(model => model.TeacherId, "TeacherId", htmlAttributes: new { @class = "control-label col-md-2" })
@Html.DropDownList("TeacherId", new SelectList(string.Empty, "Value", "Text"), "Please select a Teacher", htmlAttributes: new { @class = "form-control" })
@Html.ValidationMessageFor(model => model.TeacherId, "", new { @class = "text-danger" })
@Html.LabelFor(model => model.CreditToBeTaken, htmlAttributes: new { @class = "control-label col-md-2" })
@Html.EditorFor(model => model.CreditToBeTaken, new { @id = "creditTobeTakenTextBox", @class = "form-control" }
@Html.ValidationMessageFor(model => model.CreditToBeTaken, "", new { @class = "text-danger" })
Script File:
<script>
$(document).ready(function () {
$("#TeacherId").change(function () {
$.ajax({
url: '@Url.Action("CreditToBeTaken")',
type: 'POST',
dataType: 'json',
data: { teacherID: $("#TeacherId").val() },
contentType: 'application/json; charset=utf-8',
success: function (data) {
if (data.success) {
// fill the Credit to be taken
$("#CreditToBeTakenTextBox").val(data.creditsToBeTaken);
}
else {
// show a message in a alert or div
alert('This Teacher ID is not valid. Try again!');
}
}
});
});
});
</script>
(document).ready(function () {
("#TeacherId").change(function () {
.ajax({
url: '@Url.Action("CreditToBeTaken")',
type: 'POST',
dataType: 'json',
data: { teacherID:
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