<v-select
    v-model="identity_claim"
    :items="identity_claims"
    item-text="display_name"
    item-value="name"
    :readonly="is_readonly"
    :disabled="is_readonly"
    required
    :rules="rules.notNullRules"
    @change="identityChange(identity_claim)"
  >
  </v-select>

之前的错误写法：

export default {
	data(){
	  identity_claim: { display_name: "用户ID(默认)" },
      identity_claims: [],
	},
	methods:{
		identityChange(identity) {
	      this.identity_claim.display_name identity;
       }
    }
}

正确写法：

export default {
	data(){
	  identity_claim: { display_name: "用户ID(默认)" },
      identity_claims: [],
	},
	methods:{
		identityChange(identity) {
	      this.identity_claim = {
	        display_name: identity
	      };
       }
    }
}