docs: 补充 radios selectFirst 等文档 (#4116)

docs/zh-CN/components/form/radios.md

@@ -116,6 +116,125 @@ order: 36
 }
 ```
 
+## 默认选择第一个
+
+通过 `selectFirst` 属性配置
+
+```schema: scope="body"
+{
+  "type": "form",
+  "body": [
+    {
+      "name": "radios",
+      "type": "radios",
+      "label": "radios",
+      "selectFirst": true,
+      "options": [
+        {
+          "label": "OptionA",
+          "value": "a"
+        },
+        {
+          "label": "OptionB",
+          "value": "b"
+        },
+        {
+          "label": "OptionC",
+          "value": "c"
+        },
+        {
+          "label": "OptionD",
+          "value": "d"
+        }
+      ]
+    }
+  ]
+}
+```
+
+## 动态选项
+
+可以配置 `source` 来从上下文或远程 api 拉取选项数据
+
+```schema: scope="body"
+{
+  "type": "page",
+  "body": {
+    "type": "form",
+    "data": {
+      "items": [
+        {
+          "label": "A",
+          "value": "a"
+        },
+        {
+          "label": "B",
+          "value": "b"
+        },
+        {
+          "label": "C",
+          "value": "c"
+        }
+      ]
+    },
+    "body": [
+      {
+        "label": "选项",
+        "type": "radios",
+        "name": "radios",
+        "source": "${items}"
+      }
+    ]
+  }
+}
+```
+
+远程 api
+
+```schema: scope="body"
+{
+  "type": "page",
+  "body": {
+    "type": "form",
+    "body": [
+      {
+        "label": "选项",
+        "type": "radios",
+        "name": "radios",
+        "source": "/api/mock2/form/getOptions?waitSeconds=1"
+      }
+    ]
+  }
+}
+```
+
+api 返回内容需要包含 options 字段
+
+```json
+{
+  "status": 0,
+  "msg": "",
+  "data": {
+    "value": "b", // 可选，如果返回就会自动选中 b 选项
+    // 必须用 options 作为选项组的 key 值
+    "options": [
+      {
+        "label": "A",
+        "value": "a"
+      },
+      {
+        "label": "B",
+        "value": "b"
+      },
+      {
+        "label": "C",
+        "value": "c"
+      }
+    ]
+  }
+}
+```
+
 ## 属性表
 
 当做选择器表单项使用时，除了支持 [普通表单项属性表](./formitem#%E5%B1%9E%E6%80%A7%E8%A1%A8) 中的配置以外，还支持下面一些配置
@@ -128,17 +247,18 @@ order: 36
 | valueField   | `boolean`                                 | `"value"` | [选项值字段](./options#%E9%80%89%E9%A1%B9%E5%80%BC%E5%AD%97%E6%AE%B5-valuefield)            |
 | columnsCount | `number`                                  | `1`       | 选项按几列显示，默认为一列                                                                  |
 | inline       | `boolean`                                 | `true`    | 是否显示为一行                                                                              |
+| selectFirst  | `boolean`                                 | `false`   | 是否默认选中第一个                                                                          |
 | autoFill     | `object`                                  |           | [自动填充](./options#%E8%87%AA%E5%8A%A8%E5%A1%AB%E5%85%85-autofill)                         |
 
 ## 事件表
 
 | 事件名称 | 事件参数                         | 说明                 |
-| -------- | -------------------------------------------------------------------------------------------------- | ---- |
+| -------- | -------------------------------- | -------------------- |
 | change   | `value: string \| Option` 选中值 | 选中值发生变化时触发 |
 
 ## 动作表
 
 | 动作名称 | 动作配置 | 说明 |
-| -------- | -------------------------------------------------------------------------------------------------- | ---- |
+| -------- | -------- | ---- |
 | clear    | -        | 清空 |
 | reset    | -        | 重置 |

examples/components/Linkage/OptionsLocal.jsx

@@ -1,11 +1,12 @@
 export default {
   type: 'page',
-  title: '表单选线的联动',
+  title: '表单选项的联动',
   body: {
     type: 'form',
     mode: 'horizontal',
     title: '',
     actions: [],
+    debug: true,
     body: [
       '<p class="text-danger">表单选项内也能联动，通过配置 visibleOn、hiddenOn或者disabledOn</p>',
       {
@@ -38,11 +39,12 @@ export default {
       },
 
       {
-        label: '选项2',
+        label: '选项级别联动',
         type: 'radios',
         labelClassName: 'text-muted',
         name: 'b',
         inline: true,
+        selectFirst: true,
         options: [
           {
             label: '选项1',
@@ -62,6 +64,42 @@ export default {
             visibleOn: 'data.a == 3'
           }
         ]
+      },
+
+      {
+        label: '组件级别联动',
+        type: 'radios',
+        labelClassName: 'text-muted',
+        name: 'b',
+        inline: true,
+        selectFirst: true,
+        visibleOn: 'data.a == 1',
+        options: [
+          {
+            label: '选项1',
+            value: 1
+          }
+        ]
+      },
+
+      {
+        label: '选项级别联动',
+        type: 'radios',
+        labelClassName: 'text-muted',
+        name: 'b',
+        inline: true,
+        selectFirst: true,
+        visibleOn: 'data.a == 2',
+        options: [
+          {
+            label: '选项1',
+            value: 1
+          },
+          {
+            label: '选项2',
+            value: 2
+          }
+        ]
       }
     ]
   }