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Help With a Combo Problem

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  • C Christian Graus

    And what goes wrong ? =(int)this.cmbSubDiagnosis.SelectedValue; Is it possible that selectedValue is a string and you need Convert.ToInt16 instead of the cast ? Christian Graus - Microsoft MVP - C++

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    monica2k
    wrote on last edited by
    #9

    yes exactly the problem comes here. what to do next

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    • M monica2k

      yes exactly the problem comes here. what to do next

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      Christian Graus
      wrote on last edited by
      #10

      1. Change (int) to Convert.ToInt32( (like I said ) 2. Step through the debugger in future to see what's going on when you've got a line that blows up 3. Next time you ask a question, if you know where the code blows up, then give us the code, and either way, tell us what the error is you're getting. Christian Graus - Microsoft MVP - C++

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      • C Christian Graus

        1. Change (int) to Convert.ToInt32( (like I said ) 2. Step through the debugger in future to see what's going on when you've got a line that blows up 3. Next time you ask a question, if you know where the code blows up, then give us the code, and either way, tell us what the error is you're getting. Christian Graus - Microsoft MVP - C++

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        monica2k
        wrote on last edited by
        #11

        Its Still giving error at the same point and the error is An unhandled exception of type 'System.InvalidCastException' occurred in mscorlib.dll Additional information: Specified cast is not valid.

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        • M monica2k

          Its Still giving error at the same point and the error is An unhandled exception of type 'System.InvalidCastException' occurred in mscorlib.dll Additional information: Specified cast is not valid.

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          Christian Graus
          wrote on last edited by
          #12

          Step 2 - use the debugger to find why the Value can't cast to a number. Christian Graus - Microsoft MVP - C++

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          • C Christian Graus

            Step 2 - use the debugger to find why the Value can't cast to a number. Christian Graus - Microsoft MVP - C++

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            monica2k
            wrote on last edited by
            #13

            when i used the debugger it shows that the selectedvalue has "System.Data.DataRowView" value that is why its not converting it but what is the solution to it.

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            • M monica2k

              when i used the debugger it shows that the selectedvalue has "System.Data.DataRowView" value that is why its not converting it but what is the solution to it.

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              Christian Graus
              wrote on last edited by
              #14

              OK, so that's what you need to cast it to, and then get the value out of it. Christian Graus - Microsoft MVP - C++

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              • C Christian Graus

                OK, so that's what you need to cast it to, and then get the value out of it. Christian Graus - Microsoft MVP - C++

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                monica2k
                wrote on last edited by
                #15

                Casting to Int32 is also not working . It is giving same error Is there any other way to achive my aim.Now where should i look. I am doing nothing different. Is there any other way to fill the combo with the rows from table with their code as value member. or is there any otehr event which i can use.

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                • M monica2k

                  Casting to Int32 is also not working . It is giving same error Is there any other way to achive my aim.Now where should i look. I am doing nothing different. Is there any other way to fill the combo with the rows from table with their code as value member. or is there any otehr event which i can use.

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                  Robert Rohde
                  wrote on last edited by
                  #16

                  Instead of casting to Int32 you have to first cast to System.Data.DataRowView. If you have this you can use its indexer to access the element you need. After that cast this element to Int32 and you are done.

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                  • R Robert Rohde

                    Instead of casting to Int32 you have to first cast to System.Data.DataRowView. If you have this you can use its indexer to access the element you need. After that cast this element to Int32 and you are done.

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                    monica2k
                    wrote on last edited by
                    #17

                    how to do that can u pls explain i am new to C#

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                    • M monica2k

                      how to do that can u pls explain i am new to C#

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                      AfzalHassen
                      wrote on last edited by
                      #18

                      are you getting this problem only when the form is loading?? Afzal Hassen

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                      • M monica2k

                        how to do that can u pls explain i am new to C#

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                        Robert Rohde
                        wrote on last edited by
                        #19

                        As Im really in a hurry here just a small snippet:

                        DataRovwView drv = (DataRowView)this.cmbSubDiagnosis.SelectedValue;
                        int myIntValue = (int)drv[IndexOrNameOfTheColumnYouWishToAccess];

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                        • M monica2k

                          Casting to Int32 is also not working . It is giving same error Is there any other way to achive my aim.Now where should i look. I am doing nothing different. Is there any other way to fill the combo with the rows from table with their code as value member. or is there any otehr event which i can use.

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                          Christian Graus
                          wrote on last edited by
                          #20

                          Your core problem is that you're shoving a datarowview into the value, the problem really is when you set the data source. You need to tell the combo which property to use to set the value for each row. The problem has nothing to do with the event. You have a datarowview in the value, you cannot magically turn it into an int, you need to either get it out as a datarowview ( which is what it is ) and then work out where your number is or, preferably, you need to fix the code that sets the datasource, so that it does in fact contain an int as you were hoping. In general, these 'please help me, something blows up' posts are useless, look how long it took us to get to the heart of the problem. You should learn to use your debugger. You'll get your answer a lot quicker if you post something like 'this line throws an invalid cast exception and the value in the row that I'm trying to cast is a datarowview.' A few seconds in the debugger will tell you that, and as you learn C#, that's the path you'd follow to fix the problem, by first knowing what it is. Christian Graus - Microsoft MVP - C++

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                          • C Christian Graus

                            Your core problem is that you're shoving a datarowview into the value, the problem really is when you set the data source. You need to tell the combo which property to use to set the value for each row. The problem has nothing to do with the event. You have a datarowview in the value, you cannot magically turn it into an int, you need to either get it out as a datarowview ( which is what it is ) and then work out where your number is or, preferably, you need to fix the code that sets the datasource, so that it does in fact contain an int as you were hoping. In general, these 'please help me, something blows up' posts are useless, look how long it took us to get to the heart of the problem. You should learn to use your debugger. You'll get your answer a lot quicker if you post something like 'this line throws an invalid cast exception and the value in the row that I'm trying to cast is a datarowview.' A few seconds in the debugger will tell you that, and as you learn C#, that's the path you'd follow to fix the problem, by first knowing what it is. Christian Graus - Microsoft MVP - C++

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                            monica2k
                            wrote on last edited by
                            #21

                            Thanks i will try to follow ur instructions . monica

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