- #If the combobox addressbox contains a list of strings how to#
- #If the combobox addressbox contains a list of strings code#
Now the SQL statement will fetch only cities that are specific to the selected country and state.
#If the combobox addressbox contains a list of strings code#
The " XXX" in the SQL statement is replaced with the selected country code and " YYY" replaced with the selected state name. The codes in the states_SelectedIndexChanged subroutine will run when you select a specific state. Object, _īyVal e As System.EventArgs) Handles countries.SelectedIndexChanged Again, the SQL statement is passed to the getDataSet function to retrieve a dataset with the database data.Ĭopy Code Private Sub countries_SelectedIndexChanged( ByVal sender As System. At this point, cities will still show no data because no specific state has been selected yet. By replacing " XXX" in the SQL statement for states, we have now changed the SQL statement to get only states that are specific to the selected country. So the states dropdownlist will have to display the states for that country. What happens here is that there is a specific country selected now.
In the countries_SelectedIndexChanged subroutine, you will see what happens when you select a value in the countries dropdownlist. ( 0, New ListItem( " Please select a state.", " "))Ĭ( 0, New ListItem( " Please select a city.", " ")) SqlStr3A = sqlStr3A.Replace( " NNN", " ")Ĭ( 0, New ListItem( " Please select a country.", " ")) SqlStr2A = sqlStr2A.Replace( " NNN", " ") SqlStr3A = sqlStr3A.Replace( " NNN", " N") SqlStr2A = sqlStr2A.Replace( " NNN", " N") SqlStr3A = sqlStr3A.Replace( " YYY", currState.Replace( " '", " ''")) SqlStr3A = sqlStr3.Replace( " XXX", currCountry.Replace( " '", " ''")) SqlStr2A = sqlStr2.Replace( " XXX", currCountry.Replace( " '", " ''")) This will display by default "Please select a country." for the countries dropdownlist and similarly for the other 2 dropdownlists.Ĭountries.DataSource = getDataSet(sqlStr)Ĭountries.DataTextField = " COUNTRY_NAME"Ĭountries.DataValueField = " COUNTRY_CODE" After all 3 dropdownlists have been bound with data, we insert another option into the top of each dropdownlist. The reason for this is that having the " N" is how Microsoft SQL Server casts a value to Unicode encoding. As you can see, here we check that if isMSSQL is True, then we will replace the " NNN" to be " N". If you are using the Microsoft SQL Server database, remember to set the variable isMSSQL to True during the variable declaration. Basically what the code does is get the SQL statement and then pass it to the getDataSet function which will return a dataset with the database data. In the Page_Load subroutine, you will see the following code. The other two variables contain the SQL statements to get the data for the states and cities dropdownlists respectively.Ĭopy Code ' sample connection string for MySQL ' connStr = "DRIVER= Server=localhost _ĭatabase=countrystatecitydb Uid= Pwd= " The sqlStr variable contains the SQL statement for getting the data for the countries dropdownlist. Below is the code for file:Īt the top, you will see the variable declaration section, isMSSQL is a boolean variable which you must set to True if you are using a Microsoft SQL Server database.
This is because the moment you select a value in either of the dropdownlists, the page will reload to get new values for the next dropdownlist.Ĭopy Code ASP.NET VB Sample Īlright, now for the actual code that does all the work. Note that both the countries and states dropdownlists have AutoPostBack="True". It is a fairly simple HTML file containing 3 ASP.NET dropdownlists. Let's start off with the index.aspx file which is displayed below: The code is meant to work in Microsoft Visual Studio 2003. In this example, the 2 important files are index.aspx which contains the HTML code and the which contains the. For Microsoft SQL Server, the file is called countrystatecity-mssql-sample.sql. For MySQL, the script filename is called countrystatecity-mysql-sample.sql.
I have included a sample of the data file in the text file GEODATASOURCE-WORLD-MAJOR-CITIES-SAMPLES.TXT and to make life easier for you, I have also included 2 SQL scripts for importing into either a MySQL database or a Microsoft SQL Server database. That said, it is still quite straightforward to modify the code to work with data from other sources. The code in this article is actually custom made to use the World Major Cities data from. This article assumes that you are familiar with basic HTML as well as basic ASP.NET code. Then when you select a state, the cities dropdownlist will fetch the related cities for that state.
When you select a country in the countries dropdownlist, the states dropdownlist will fetch the related states for that country.
#If the combobox addressbox contains a list of strings how to#
This article aims to show how to create 3 dropdownlists to display countries, states and cities.
0 kommentar(er)
