if condition problem?

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C#

if (TextBox1.Text == null)
        {
        Label1.Text = "Input Valid values";
        }
        else {
            sLong1 = geocodeXmlDoc1.DocumentElement.SelectSingleNode(@"//geometry/location/lat", XmlMngr1).InnerText;
            sLat1 = geocodeXmlDoc1.DocumentElement.SelectSingleNode(@"//geometry/location/lng", XmlMngr1).InnerText;

            sLong2 = geocodeXmlDoc2.DocumentElement.SelectSingleNode(@"//geometry/location/lat", XmlMngr2).InnerText;
            sLat2 = geocodeXmlDoc2.DocumentElement.SelectSingleNode(@"//geometry/location/lng", XmlMngr2).InnerText;

            Label1.Text = sLong1 + ", " + sLat1;
            Label2.Text = sLong2 + ", " + sLat2;


        }

the concept of this is
i want to check if the textbox value is null or not

i put a if condition like this

but its not working...........

when i keep text box in null value
it will not go to the if condition

straightly point to the else code and point to the slong1 value and gives error saying

Object reference not set to an instance of an object.

Posted 15-Jul-13 2:36am

promod madushan

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3 solutions

Solution 4

There are various approaches you can do to this,

personally I would go with one of the following:

If the .Net framework version you are using is less than version 4

C#

if(String.IsNullOrEmpty(TextBox1.Text.Trim())

else go with:

C#

if(String.IsNullOrWhiteSpace(TextBox1.Text ))

The latter approach does not require you to trim the string first as it will detect if the string is just whitespace characters such as space, carriage returns etc.

Posted 15-Jul-13 3:02am

Pheonyx

Solution 3

if you want to check if there is only white spaces then you can do

if (TextBox1.Text.Trim() == "")
        {
        Label1.Text = "Input Valid values";
        }
        else {
            sLong1 = geocodeXmlDoc1.DocumentElement.SelectSingleNode(@"//geometry/location/lat", XmlMngr1).InnerText;
            sLat1 = geocodeXmlDoc1.DocumentElement.SelectSingleNode(@"//geometry/location/lng", XmlMngr1).InnerText;
 
            sLong2 = geocodeXmlDoc2.DocumentElement.SelectSingleNode(@"//geometry/location/lat", XmlMngr2).InnerText;
            sLat2 = geocodeXmlDoc2.DocumentElement.SelectSingleNode(@"//geometry/location/lng", XmlMngr2).InnerText;
 
            Label1.Text = sLong1 + ", " + sLat1;
            Label2.Text = sLong2 + ", " + sLat2;
 
 
        }

Posted 15-Jul-13 2:54am

bunzitop

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**Nirav Prabtani** · Accepted Answer · 2013-07-15T02:41:00

Try this..... :)

C#

if (TextBox1.Text == "")
        {
        Label1.Text = "Input Valid values";
        }
        else {
            sLong1 = geocodeXmlDoc1.DocumentElement.SelectSingleNode(@"//geometry/location/lat", XmlMngr1).InnerText;
            sLat1 = geocodeXmlDoc1.DocumentElement.SelectSingleNode(@"//geometry/location/lng", XmlMngr1).InnerText;
 
            sLong2 = geocodeXmlDoc2.DocumentElement.SelectSingleNode(@"//geometry/location/lat", XmlMngr2).InnerText;
            sLat2 = geocodeXmlDoc2.DocumentElement.SelectSingleNode(@"//geometry/location/lng", XmlMngr2).InnerText;
 
            Label1.Text = sLong1 + ", " + sLat1;
            Label2.Text = sLong2 + ", " + sLat2;
 

        }