How to create multilingual application in asp.net

Step - 1 : Create New Project.

Go to File > New > Project > Select asp.net web forms application > Entry Application Name > Click OK.

Step-2: Add a Webpage and Design for make a form multilingual.

Go to Solution Explorer > Right Click on Project name form Solution Explorer > Add > New item > Select web form/ web form using master page under Web > Enter page name > Add.


HTML Code 

            <div style="text-align:right;">
                <asp:DropDownList ID="ddLang" runat="server" AutoPostBack="true" OnSelectedIndexChanged="ddLang_SelectedIndexChanged">
                    <asp:ListItem Value="en-US" Text="English" />
                    <asp:ListItem Value="fr-FR" Text="français" />
                    <asp:ListItem Value="hi-IN" Text="हिंदी" />
                </asp:DropDownList>
            </div>
            <table>
                <tr>
                    <td><asp:Label ID="lblName" runat="server"/></td>
                    <td><asp:TextBox ID="txtName" runat="server" /></td>
                </tr>
                <tr>
                    <td><asp:Label ID="lblAddress" runat="server" /></td>
                    <td><asp:TextBox ID="txtAddress" runat="server" /></td>
                </tr>
                <tr>
                    <td><asp:Label ID="lblState" runat="server" /></td>
                    <td><asp:TextBox ID="txtState" runat="server" /></td>
                </tr>
                <tr>
                    <td><asp:Label ID="lblCountry" runat="server" /></td>
                    <td><asp:TextBox ID="txtCountry" runat="server" /></td>
                </tr>
                <tr>
                    <td></td>
                    <td>
                        <asp:Button ID="btnSave" runat="server" /> &nbsp; &nbsp;
                        <asp:Button ID="btnCancel" runat="server" />
                    </td>
                </tr>
            </table>
        

Step-3: Add a ASP.NET Folder "App_GlobalResources" for save language resource file

Go to Solution Explorer > Right Click on Project name form Solution Explorer > Add > Add ASP.NET Folder > App_GlobalResources.

Step-4: Add Resources file for save different language under "App_GlobalResources" Folder

Right Click on "App_GlobalResources" Folder form Solution Explorer > Add > New Item > Select "Resources File" under Visual C# > Enter Name (Like "Lang.en-US.resx") > Add. 
[N:B: Please take care of the file Name.] 
Here I have added 3 file for 3 languages. 

Language	File Name
English	Lang.en-US.resx
French	Lang.fr-FR.resx
Hindi	Lang.hi-IN.resx

Step-5: Change Build Action to "Embedded Resource" of added resource files (3 added files here)

Select Resource file > Right Click go to Property> Change Build Action to Embedded Resource. 

Step-6: Write code into page load event for show selected language.

Write below code into Page_Load event. 
We need to import following Namespace first.. 

            using System.Resources;
            using System.Globalization;
            using System.Threading;
            using System.Reflection;
        

            ResourceManager rm;
            CultureInfo ci;
            protected void Page_Load(object sender, EventArgs e)
            {
                if (Session["Lang"] == null)
                {
                    Session["Lang"] = Request.UserLanguages[0];
                }
 
                if (!IsPostBack)
                {
                    LoadString();
                }
            }
        

Here is the function...

            private void LoadString()
            {
                Thread.CurrentThread.CurrentCulture = new CultureInfo(Session["Lang"].ToString());
                rm = new ResourceManager("MultiLingual.App_GlobalResources.Lang", Assembly.GetExecutingAssembly());
                ci = Thread.CurrentThread.CurrentCulture;
 
                lblName.Text = rm.GetString("Name", ci);
                lblAddress.Text = rm.GetString("Address", ci);
                lblState.Text = rm.GetString("State", ci);
                lblCountry.Text = rm.GetString("Country", ci);
                btnSave.Text = rm.GetString("Save", ci);
                btnCancel.Text = rm.GetString("Cancel", ci);
            }
        

Step-7: Write code into "ddLang_SelectedIndexChanged" event for show selected language.

           protected void ddLang_SelectedIndexChanged(object sender, EventArgs e)
            {
                Session["Lang"] = ddLang.SelectedValue;
                LoadString();
            }
        

Step-8: Run Application.