How would I bind a SqlDatasource ConnectionString property to a function

Question

I am trying to set the ConnectionString property to the return value of a function in the ASPX page.

Example:

<asp:SqlDataSource runat="server" id="blah"
    ConnectionString="<%= ServerSensing.GetConnectionStringByServer("someKey"); %>"
    >
    ...
</asp:SqlDataSource>

The above is obviously not going to work.. so.. what will?

Preemptive remarks: * No, I can not use the Web.config binding

Answer 1

Can you set the connection string in the code behind?

Answer 2

you should be able to set it in your Page_Load, something like:

blah.ConnectionString = ServerSensing.GetConnectionStringByServer("someKey");

or if you dont have access to the code behind put some inline code on the page, like.. (just before the markup for the SqlDataSource)

<%
     blah.ConnectionString = ServerSensing.GetConnectionStringByServer("someKey");
%>

Answer 3

The best way i've found about this question is using Expression Builder in your solution.

With this feature you can create a custom inline expression and use it in the SqlDataSource tag.

Yuo'll find some examples right here:

http://weblogs.asp.net/infinitiesloop/archive/2006/08/09/The-CodeExpressionBuilder.aspx

That's how i implemented in my apps:

---

[ExpressionPrefix("RepConnectionString")]

public class RepConnectionStringExpressionBuilder : ExpressionBuilder { public override CodeExpression GetCodeExpression(BoundPropertyEntry entry, object parsedData, ExpressionBuilderContext context) { CodeTypeReferenceExpression thisType = new CodeTypeReferenceExpression(base.GetType());

    CodePrimitiveExpression expression = new CodePrimitiveExpression(entry.Expression.Trim().ToString());

    string evaluationMethod = "GetConnectionString";

    return new CodeMethodInvokeExpression(thisType, evaluationMethod, new CodeExpression[] { expression });
}


public static string GetConnectionString(string expression)
{
    XmlDocument xmlDoc = new XmlDocument();
    string wPath = HttpContext.Current.Server.MapPath("~/XmlFile.xml");
    xmlDoc.Load(wPath);
    XmlNode wNode = xmlDoc.SelectSingleNode("Autenticacoes/Database[@id='" + expression + "']");

    string wConnString = "";
    if (wNode != null)
    {
        wConnString = "Data Source=" + wNode.Attributes["servidor"].Value + ";Initial Catalog=" + wNode.Attributes["db"].Value + ";Persist Security Info=True;User ID=" + wNode.Attributes["login"].Value + ";Password=" + wNode.Attributes["senha"].Value;
    }

    return wConnString;
}

}

---

in the web.config:

<compilation>
  <expressionBuilders>
    <add expressionPrefix="RepConnectionString" type="RepConnectionStringExpressionBuilder"/>
  </expressionBuilders>