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scala - 如何在 Lift 中动态生成输入表单

转载 作者:行者123 更新时间:2023-12-02 00:25:10 25 4
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我正在开发我的第一个 Lift 项目,并且需要动态生成表单。更准确地说,我有一些由对象表示的操作,这些对象附加了参数列表 - 其中一些是字符串,一些数字,一些 bool 值,一些文件。我需要通过表单为其参数提供操作对象的具体值。目前,我只是遍历参数列表并直接以 XML 形式生成表单,但我知道这是极其糟糕的风格 - 我无法绑定(bind)输入值,无法绑定(bind)要提交的操作,无法应用验证。我被困在传递请求参数上,但我想解决这个问题。不幸的是我必须想出如何做到这一点,所以任何帮助将不胜感激。我不断发现的所有示例始终预先有固定数量的输入参数。

这里有一些相关代码。我希望它足够容易理解(而且我真的很羞于公开展示它:-))

def operationForm(): NodeSeq = {
val operationCode = S.param("operation").openOr("")
val operationVariant = S.param("operationVariant").openOr("")

if (operationCode != "" && !operationVariant.isEmpty) {
val operation = LighthouseDAOs.operationsRegistry.findByCode(operationCode)
val params: List[Parameter] = if (operationVariant == "default") {
operation.getParameters.toList
} else {
operation.getParameters.filter(p => p.getVariant == operationVariant).toList
}

<lift:surround with="closableBox" at="content">
<form id="viewOperation" post={"/Deployment/" + S.param("location") + "/" + S.param("deployment")} method="post">
{params.map(p => getInputElem(p))}
<input type="submit" style="width: 150px;" value="Execute operation"/>
<input type="hidden" name="executeOperation" value="true"/>
</form>
</lift:surround>
} else {
<span></span>
}
}

private def getOperationVariants(operation: Operation): Set[String] = {
operation.getParameters.map(_.getVariant).toSet
}

def operationVariants(deployment: Deployment): NodeSeq = {
val operationCode = S.param("operation").openOr("")

if (operationCode != "") {
val operation = LighthouseDAOs.operationsRegistry.findByCode(operationCode)

val variants = getOperationVariants(operation)

if (variants.size > 1) {
<lift:surround with="closableBox" at="content">
<table cellspacing="0" cellpadding="0" border="0">
<tr>
<th style="width: 160px;">Operation
{operation.getLongName}
variants</th>
</tr>{variants.map(v => {
<tr>
<td>
<a href={Path.path + "Deployment/" + encode(deployment.getLocation) + "/" + encode(deployment.getDeployedComponent.getCode) + "?operation=" + encode(operation.getCode) + "&operationVariant=" + encode(v)}>
{v}
</a>
</td>
</tr>
})}
</table>
</lift:surround>
} else {
<span></span>
}
} else {
<span></span>
}
}

def getInputElem(param: Parameter): Node = {
if (param.getChoice != null) {
<div>
<label for={param.getName}>
{param.getName}
</label>
<select id={param.getName} name={param.getName}>
{param.getChoice.flatMap(c => <option value={c}>
{c}
</option>)}
</select>
</div>
} else {

val paramType = param.getType match {
case Parameter.PASSWORD => "password"
case Parameter.BOOLEAN => "checkbox"
case Parameter.CLOB => "file"
case _ => "text"
}

<div>
<label for={param.getName}>
{param.getName}
:</label> <input type={paramType} id={param.getName} name={param.getName} stype="width: 300px;">
{param.getDefaultValue}
</input>
</div>
}
}

def executeOperation(deployment: Deployment): Elem = {
val operationCode = S.param("operation").openOr("")
val operationVariant = S.param("operationVariant").openOr("")

if (S.param("executeOperation").openOr("false") == "true") {
val op = LighthouseDAOs.operationsRegistry.findByCode(operationCode)
val params = op.getParameters

LogLH3.info("Executing operation: " + op.getLongName)

val operationInstallation = new OperationInstallation();
operationInstallation.setInstallationLocation(deployment);
operationInstallation.setInstalledOperation(op);

val operationCall = new OperationCall(operationInstallation);
if (operationVariant != "" && operationVariant != "default")
operationCall.setVariant(operationVariant)

params.filter(p => p.getVariant == operationVariant).foreach(p => operationCall.addParameterValue(op.createParameterValue(p.getName, S.param(p.getName).openOr(""))))

try {
LighthouseDAOs.operationInstallationRegistry.execute(operationCall)
S.notice("Operation " + op.getLongName + " was executed successfully.")
} catch {
case e: Exception => S.error(e.getMessage)
}
}

<span></span>
}

仅供记录,我正在使用 Lift 2.2 和 Scala 2.8.1

最佳答案

您可以改进这个示例,使其对设计人员更加友好,但这是基本思想。当然,您需要以某种形式包装它。

基本上,您有一个模板,并将其内容替换为使用 CSS 选择器绑定(bind)动态生成的内容。

在您的模板中:

<div class="lift:MyForm.render">
Form will go here
</div>

代码片段:

class MyForm extends Snippet {
def render = {
val fields = List("a", "b", "c")
var params: Map[String, String] = ... //or whatever

def setf(key: String)(value: String) = params = params.updated(key, value)
def getf(key: String)() = params.get(key)

"*" #> fields map {
field =>
<p>
<label>{field}</label>{SHtml.text(getf(field) _, setf(field) _)}
</p>
}
}
}

关于scala - 如何在 Lift 中动态生成输入表单,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/5663058/

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