Question

我有一个自定义控件，可以为表单生成标签输入对。我希望标签的文本由名称字段而不是ID字段控制。但是，当我进入自定义控件并显式设置我的标签的文本字段等于名称时，标签的文本始终是我的自定义控件的ID。为什么呢？

页面上的表格：

<FormUpgrade:FormUpgrade ID="fname" type="text" name="First Name" runat="server" />

在我的oninit函数中，我有以下几行：

aLabel.Text = name;
this.Controls.Add(this.aLabel);

aLabel之后永远不会被触及。

但是，如果我手动键入我的标签字段，则“文本”字段的行为与预期一致。

以下是整个自定义控件的代码：

namespace FormUpgrade
{
    [DefaultProperty("Text")]
    [ToolboxData("<{0}:FormUpgrade runat=server></{0}:FormUpgrade>")]
    public class FormUpgrade : WebControl
    {
        [Bindable(true)]
        [Category("Appearance")]
        [DefaultValue("")]
        [Localizable(true)]

        public Label aLabel = new Label();
        public TextBox aField = new TextBox();
        public RegularExpressionValidator regexvalid = new RegularExpressionValidator();

        protected override void OnInit(EventArgs e)
        {
            regexvalid.ID = ID + "_validator";

            if (!String.IsNullOrEmpty(ID))
            {
                aField.ID = ID+"_box";
                aLabel.ID = ID + "_label";
                aLabel.AssociatedControlID = aLabel.ID;
            }

            //aField.Attributes.Add("runat", "server");
            // aLabel.Attributes.Add("runat", "server");


            if (!String.IsNullOrEmpty(required))
            {
                aField.Attributes.Add("required", required);
                if (required.Equals("required"))
                {
                    aLabel.Attributes.Add("class", "required");
                }
            }

            if (!String.IsNullOrEmpty(name))
            {
                aField.Attributes.Add("name", name);
                aLabel.Text = name;
            }
            else
            {
                aLabel.Text = ID;
            }

            if (!String.IsNullOrEmpty(placeholder))
            {
                aField.Attributes.Add("placeholder", placeholder);
            }

            if (!String.IsNullOrEmpty(role))
            {
                aField.Attributes.Add("role", role);
            }

            if (!String.IsNullOrEmpty(maxlength))
            {
                aField.Attributes.Add("maxlength", maxlength);
            }

            if (!String.IsNullOrEmpty(placeholder))
            {
                aField.Attributes.Add("placeholder", placeholder);
            }

            aLabel.Attributes.Add("for", ID+"_box");

            if (!String.IsNullOrEmpty(type))
            {
                aField.Attributes.Add("type", type);
            }

            //if (type.Equals("date"))
            //{
            //    aField.Attributes.Add("class", "hasDatepicker");
            //}

            if(type.Equals("textarea"))
            {
                aField.TextMode = TextBoxMode.MultiLine;
            }

            if (type.Equals("password"))
            {
                aField.TextMode = TextBoxMode.Password;
            }

            aLabel.Text = name;

            this.Controls.Add(this.aLabel);
            this.Controls.Add(this.aField);

            if(type.Equals("email"))
            {
                regexvalid.ValidationExpression = "[a-zA-Z0-9]+([-+.][a-zA-Z0-9]+)*@[a-zA-Z0-9]+([-.][a-zA-Z0-9]+)*.[a-zA-Z0-9]+([-.][a-zA-Z0-9]+)*";
                regexvalid.ControlToValidate = ID+"_box";
                regexvalid.ErrorMessage = "Not a valid email address <br>";

                this.Controls.Add(regexvalid);
            }
            else if (type.Equals("url"))
            {
                regexvalid.ValidationExpression = "http(s)?://([a-zA-Z0-9-]+.)+[a-zA-Z0-9-]+(/[a-zA-Z0-9- ./?%&=]*)?";
                regexvalid.ControlToValidate = ID + "_box";
                regexvalid.ErrorMessage = "Not a valid URL<br>";

                this.Controls.Add(regexvalid);
            } 
            else if(!String.IsNullOrEmpty(ValidationExpression))
            {
                  regexvalid.ControlToValidate = ID + "_box";
                  regexvalid.ValidationExpression = ValidationExpression;

                  if (!String.IsNullOrEmpty(ValidationErrorMessage))
                  {
                      regexvalid.ErrorMessage = ValidationErrorMessage + "<br>";
                  }

                  this.Controls.Add(regexvalid);
           }

            base.OnInit(e);
        }

        public string Text
        {
            get
            {
                String s = (String)ViewState["Text"];
                return ((s == null) ? "[" + this.ID + "]" : s);
            }
            set
            {
                ViewState["Text"] = value;
            }
        }

        public string type
        {
            get
            {
                String s = (String)ViewState["type"];
                return ((s == null) ? "[" + this.ID + "]" : s);
            }
            set
            {
                ViewState["type"] = value;
            }
        }

        public string name
        {
            get
            {
                String s = (String)ViewState["name"];
                return ((s == null) ? "" : s);
            }
            set
            {
                ViewState["name"] = value;
            }
        }

        public string required
        {
            get
            {
                String s = (String)ViewState["required"];
                return ((s == null) ? "" : s);
            }
            set
            {
                ViewState["required"] = value;
            }
        }

        public string role
        {
            get
            {
                String s = (String)ViewState["role"];
                return ((s == null) ? "" : s);
            }
            set
            {
                ViewState["role"] = value;
            }
        }

        public string ValidationExpression
        {
            get
            {
                String s = (String)ViewState["ValidationExpression"];
                return ((s == null) ? "" : s);
            }
            set
            {
                ViewState["ValidationExpression"] = value;
            }
        }

        public string ValidationErrorMessage
        {
            get
            {
                String s = (String)ViewState["ValidationErrorMessage"];
                return ((s == null) ? "" : s);
            }
            set
            {
                ViewState["ValidationErrorMessage"] = value;
            }
        }

        public string placeholder
        {
            get
            {
                String s = (String)ViewState["placeholder"];
                return ((s == null) ? "" : s);
            }
            set
            {
                ViewState["placeholder"] = value;
            }
        }

        public string Display
        {
            get
            {
                String s = (String)ViewState["Display"];
                return ((s == null) ? "" : s);
            }
            set
            {
                ViewState["Display"] = value;
            }
        }

        public string maxlength
        {
            get
            {
                String s = (String)ViewState["maxlength"];
                return ((s == null) ? "" : s);
            }
            set
            {
                ViewState["maxlength"] = value;
            }
        }

        public string Value
        {
            get
            {
                String s = (String)ViewState["Value"];
                return ((s == null) ? "" : s);
            }
            set
            {
                ViewState["Value"] = value;
            }
        }

        public override void RenderBeginTag(HtmlTextWriter writer)
        {
        }

        public override void RenderEndTag(HtmlTextWriter writer)
        {
        }

    }
}

Answer 1

看起来问题可能就在这里：

public string Text 
{ 
    get 
    { 
        String s = (String)ViewState["Text"]; 
        return ((s == null) ? "[" + this.ID + "]" : s); 
    } 

    set 
    { 
        ViewState["Text"] = value; 
    } 
}

我认为s返回null，而是返回ID。如果Text为空，请尝试返回空字符串。

标签不起作用的.text字段

1 个答案: