基于下拉列表选择验证文本框

我想验证基于选定的下拉列表的值的文本框。基本上我想要做的是验证以确保信用卡号码以4开头，如果选择签证或选择5如果mastercard被选中。我也想根据给定的卡类型验证字符串的长度。这是我到目前为止。基于下拉列表选择验证文本框

  <p> 
       Card Type:* <br /> 
       <asp:DropDownList ID="cardType" runat="server" AutoPostBack="True"> 
        <asp:ListItem>Visa</asp:ListItem> 
        <asp:ListItem>Mastercard</asp:ListItem> 
        <asp:ListItem>Amex</asp:ListItem> 
       </asp:DropDownList> 
      </p> 
      <p> 
       Card Number:* <br /> 
       <asp:TextBox ID="cardNumber" runat="server"></asp:TextBox> 
       <asp:RequiredFieldValidator ID="RequiredFieldValidator11" runat="server" 
        ErrorMessage="Please enter Card Number" ControlToValidate="cardNumber"></asp:RequiredFieldValidator> 
       <asp:RegularExpressionValidator ID="RegularExpressionValidator4" runat="server" 
        ControlToValidate="cardNumber" validationExpression="^\d+$" ErrorMessage="please only enter numbers"></asp:RegularExpressionValidator> 
       <asp:CustomValidator ID="CustomValidator1" runat="server" 
        ControlToValidate="cardNumber" ErrorMessage="Please enter correct number"></asp:CustomValidator> 
      </p> 
      <p> 
       Security Code:* <br /> 
       <asp:TextBox ID="securityCode" runat="server"></asp:TextBox> 
       <asp:RequiredFieldValidator ID="RequiredFieldValidator12" runat="server" 
        ErrorMessage="Please enter Security Code" ControlToValidate="securityCode"></asp:RequiredFieldValidator> 
        <asp:RegularExpressionValidator ID="RegularExpressionValidator5" runat="server" 
        ControlToValidate="securityCode" validationExpression="^\d+$" ErrorMessage="please only enter numbers"></asp:RegularExpressionValidator> 
         <asp:RegularExpressionValidator ID="RegularExpressionValidator6" runat="server" 
        ControlToValidate="securityCode" validationExpression="^\d\d\d?$" ErrorMessage="please only enter three numbers"></asp:RegularExpressionValidator> 

      </p> 
      <p> 
       Expiration Date:* <br /> 
       <asp:TextBox ID="expDate" runat="server"></asp:TextBox> 
       <asp:RequiredFieldValidator ID="RequiredFieldValidator13" runat="server" 
        ErrorMessage="Please enter Expiration Date" ControlToValidate="expDate"></asp:RequiredFieldValidator> 
       <asp:CompareValidator ID="dateValidator" runat="server" type="Date" ControlToValidate="expDate" Operator="DataTypeCheck" 
        ErrorMessage="please enter a valid date (mm/dd/yy)"></asp:CompareValidator> 
      </p> 

      &nbsp;<asp:Button ID="btnSubmit" runat="server" 
        Text="Submit" />

来源

2013-04-29 Mccoy85

您可以实现类似如下：

protected void btnSubmit_Click(object sender, EventArgs e) 
{ 
    /*find length of the string using string.Length method*/ 
     int a = cardNumber.Text.Length; 
    if(a<=your desired value) 
    { 
     /*give invalid length error*/ 
    } 
    else 
    { 
     if (cardType.SelectedValue == "Visa") 
     { 
      string str = cardNumber.Text; 
      string firstChar = str.Substring(0, 1); 
      if (firstChar != "4") 
      { 
       /*perform operation for invalid number*/ 

      } 
      else 
      { 
       /*perform operation for valid number*/ 
      } 
     } 
     else if(cardType.SelectedValue == "MasterCard") 
     { 
      string str = cardNumber.Text; 
      string firstChar = str.Substring(0, 1); 
      if (firstChar != "5") 
      { 
       /*perform operation for invalid number*/ 

      } 
      else 
      { 
       /*perform operation for valid number*/ 
      }     
     } 
    } 
}

来源

2013-04-29 05:30:41

我认为，所有你需要做的是设置在CardType.SelectedIndexChanged事件相应的验证表达式。其余的应该自动跟随：

Private Sub cardType_SelectedIndexChanged(sender As System.Object, e As System.EventArgs) Handles cardType.SelectedIndexChanged 
    Select Case cardType.SelectedValue 
     Case "Visa" 
      RegularExpressionValidator4.validationExpression = "^4\d{15}$" '-- 4 + any 15 digits 
     Case "Mastercard" 
      RegularExpressionValidator4.validationExpression = "^5\d{15}$" '-- 5 + any 15 digits 
     Case "Amex" 
      RegularExpressionValidator4.validationExpression = "^\d+$"  '-- set this one also appropriately 
    End Select 
End Sub

来源

2013-04-29 23:18:08

基于下拉列表选择验证文本框

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